diff --git a/src/rpc/channels.ts b/src/rpc/channels.ts
index 46f522777a..7be70fa96d 100644
--- a/src/rpc/channels.ts
+++ b/src/rpc/channels.ts
@@ -23,9 +23,10 @@ export type Binary = string;
 export interface Channel extends EventEmitter {
 }
 
-export type SerializedValue = undefined | boolean | number | string | ComplexSerializedValue;
-
-export type ComplexSerializedValue = {
+export type SerializedValue = {
+  n?: number,
+  b?: boolean,
+  s?: string,
   v?: 'null' | 'undefined' | 'NaN' | 'Infinity' | '-Infinity' | '-0',
   d?: string,
   r?: {
@@ -863,7 +864,7 @@ export type FrameEvalOnSelectorParams = {
   arg: SerializedArgument,
 };
 export type FrameEvalOnSelectorResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type FrameEvalOnSelectorAllParams = {
   selector: string,
@@ -872,7 +873,7 @@ export type FrameEvalOnSelectorAllParams = {
   arg: SerializedArgument,
 };
 export type FrameEvalOnSelectorAllResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type FrameAddScriptTagParams = {
   url?: string,
@@ -941,7 +942,7 @@ export type FrameEvaluateExpressionParams = {
   arg: SerializedArgument,
 };
 export type FrameEvaluateExpressionResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type FrameEvaluateExpressionHandleParams = {
   expression: string,
@@ -1119,7 +1120,7 @@ export type WorkerEvaluateExpressionParams = {
   arg: SerializedArgument,
 };
 export type WorkerEvaluateExpressionResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type WorkerEvaluateExpressionHandleParams = {
   expression: string,
@@ -1154,7 +1155,7 @@ export type JSHandleEvaluateExpressionParams = {
   arg: SerializedArgument,
 };
 export type JSHandleEvaluateExpressionResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type JSHandleEvaluateExpressionHandleParams = {
   expression: string,
@@ -1179,7 +1180,7 @@ export type JSHandleGetPropertyResult = {
 };
 export type JSHandleJsonValueParams = {};
 export type JSHandleJsonValueResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 
 // ----------- ElementHandle -----------
@@ -1219,7 +1220,7 @@ export type ElementHandleEvalOnSelectorParams = {
   arg: SerializedArgument,
 };
 export type ElementHandleEvalOnSelectorResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type ElementHandleEvalOnSelectorAllParams = {
   selector: string,
@@ -1228,7 +1229,7 @@ export type ElementHandleEvalOnSelectorAllParams = {
   arg: SerializedArgument,
 };
 export type ElementHandleEvalOnSelectorAllResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type ElementHandleBoundingBoxParams = {};
 export type ElementHandleBoundingBoxResult = {
@@ -1642,7 +1643,7 @@ export type ElectronApplicationEvaluateExpressionParams = {
   arg: SerializedArgument,
 };
 export type ElectronApplicationEvaluateExpressionResult = {
-  value?: SerializedValue,
+  value: SerializedValue,
 };
 export type ElectronApplicationEvaluateExpressionHandleParams = {
   expression: string,
diff --git a/src/rpc/client/jsHandle.ts b/src/rpc/client/jsHandle.ts
index 312c2079f9..13812e7035 100644
--- a/src/rpc/client/jsHandle.ts
+++ b/src/rpc/client/jsHandle.ts
@@ -17,7 +17,7 @@
 import { JSHandleChannel, JSHandleInitializer, SerializedArgument, SerializedValue, Channel } from '../channels';
 import { ElementHandle } from './elementHandle';
 import { ChannelOwner } from './channelOwner';
-import { serializeAsCallArgument, parseEvaluationResultValue } from '../../common/utilityScriptSerializers';
+import { parseSerializedValue, serializeValue } from '../serializers';
 
 type NoHandles<Arg> = Arg extends JSHandle ? never : (Arg extends object ? { [Key in keyof Arg]: NoHandles<Arg[Key]> } : Arg);
 type Unboxed<Arg> =
@@ -99,14 +99,14 @@ export function serializeArgument(arg: any): SerializedArgument {
     handles.push(channel);
     return handles.length - 1;
   };
-  const value = serializeAsCallArgument(arg, value => {
+  const value = serializeValue(arg, value => {
     if (value instanceof JSHandle)
       return { h: pushHandle(value._channel) };
     return { fallThrough: value };
-  });
+  }, new Set());
   return { value, handles };
 }
 
-export function parseResult(arg: SerializedValue): any {
-  return parseEvaluationResultValue(arg as any, []);
+export function parseResult(value: SerializedValue): any {
+  return parseSerializedValue(value, undefined);
 }
diff --git a/src/rpc/protocol.pdl b/src/rpc/protocol.pdl
index b2bdb403eb..491cbbac89 100644
--- a/src/rpc/protocol.pdl
+++ b/src/rpc/protocol.pdl
@@ -12,14 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-union SerializedValue
-  undefined
-  boolean
-  number
-  string
-  ComplexSerializedValue
-
-type ComplexSerializedValue
+# Exactly one of the optional fields must be present.
+type SerializedValue
+  n?: number
+  b?: boolean
+  s?: string
   v?: enum
     null
     undefined
@@ -27,16 +24,21 @@ type ComplexSerializedValue
     Infinity
     -Infinity
     -0
+  # String representation of the Date.
   d?: string
+  # Regular expression pattern and flags.
   r?: object
     p: string
     f: string
   a?: SerializedValue[]
+  # Object with keys and values.
   o?: object[]
     k: string
     v: SerializedValue
+  # An index in the handles array from SerializedArgument.
   h?: number
 
+# Represents a value with handle references.
 type SerializedArgument
   value: SerializedValue
   handles: Channel[]
@@ -756,7 +758,7 @@ interface Frame
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evalOnSelectorAll
     parameters
@@ -765,7 +767,7 @@ interface Frame
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command addScriptTag
     parameters
@@ -846,7 +848,7 @@ interface Frame
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evaluateExpressionHandle
     parameters
@@ -1031,7 +1033,7 @@ interface Worker
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evaluateExpressionHandle
     parameters
@@ -1057,7 +1059,7 @@ interface JSHandle
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evaluateExpressionHandle
     parameters
@@ -1081,7 +1083,7 @@ interface JSHandle
 
   command jsonValue
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
 interface ElementHandle extends JSHandle
   command evalOnSelector
@@ -1091,7 +1093,7 @@ interface ElementHandle extends JSHandle
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evalOnSelectorAll
     parameters
@@ -1100,7 +1102,7 @@ interface ElementHandle extends JSHandle
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command boundingBox
     returns
@@ -1458,7 +1460,7 @@ interface ElectronApplication
       isFunction: boolean
       arg: SerializedArgument
     returns
-      value?: SerializedValue
+      value: SerializedValue
 
   command evaluateExpressionHandle
     parameters
diff --git a/src/rpc/serializers.ts b/src/rpc/serializers.ts
index e4349b6840..b6702c9066 100644
--- a/src/rpc/serializers.ts
+++ b/src/rpc/serializers.ts
@@ -21,18 +21,20 @@ import * as util from 'util';
 import { TimeoutError } from '../errors';
 import * as types from '../types';
 import { helper, assert } from '../helper';
-import { SerializedError, AXNode } from './channels';
-import { serializeAsCallArgument, parseEvaluationResultValue } from '../common/utilityScriptSerializers';
+import { SerializedError, AXNode, SerializedValue } from './channels';
 
 export function serializeError(e: any): SerializedError {
   if (helper.isError(e))
     return { error: { message: e.message, stack: e.stack, name: e.name } };
-  return { value: serializeAsCallArgument(e, value => ({ fallThrough: value })) };
+  return { value: serializeValue(e, value => ({ fallThrough: value }), new Set()) };
 }
 
 export function parseError(error: SerializedError): Error {
-  if (!error.error)
-    return parseEvaluationResultValue(error.value as any, []);
+  if (!error.error) {
+    if (error.value === undefined)
+      throw new Error('Serialized error must have either an error or a value');
+    return parseSerializedValue(error.value, undefined);
+  }
   if (error.error.name === 'TimeoutError') {
     const e = new TimeoutError(error.error.message);
     e.stack = error.error.stack || '';
@@ -169,3 +171,117 @@ export function axNodeFromProtocol(axNode: AXNode): types.SerializedAXNode {
   delete (result as any).valueString;
   return result;
 }
+
+export function parseSerializedValue(value: SerializedValue, handles: any[] | undefined): any {
+  if (value.n !== undefined)
+    return value.n;
+  if (value.s !== undefined)
+    return value.s;
+  if (value.b !== undefined)
+    return value.b;
+  if (value.v !== undefined) {
+    if (value.v === 'undefined')
+      return undefined;
+    if (value.v === 'null')
+      return null;
+    if (value.v === 'NaN')
+      return NaN;
+    if (value.v === 'Infinity')
+      return Infinity;
+    if (value.v === '-Infinity')
+      return -Infinity;
+    if (value.v === '-0')
+      return -0;
+  }
+  if (value.d !== undefined)
+    return new Date(value.d);
+  if (value.r !== undefined)
+    return new RegExp(value.r.p, value.r.f);
+  if (value.a !== undefined)
+    return value.a.map((a: any) => parseSerializedValue(a, handles));
+  if (value.o !== undefined) {
+    const result: any = {};
+    for (const { k, v } of value.o)
+      result[k] = parseSerializedValue(v, handles);
+    return result;
+  }
+  if (value.h !== undefined) {
+    if (handles === undefined)
+      throw new Error('Unexpected handle');
+    return handles[value.h];
+  }
+  throw new Error('Unexpected value');
+}
+
+export type HandleOrValue = { h: number } | { fallThrough: any };
+export function serializeValue(value: any, handleSerializer: (value: any) => HandleOrValue, visited: Set<any>): SerializedValue {
+  const handle = handleSerializer(value);
+  if ('fallThrough' in handle)
+    value = handle.fallThrough;
+  else
+    return handle;
+
+  if (visited.has(value))
+    throw new Error('Argument is a circular structure');
+  if (typeof value === 'symbol')
+    return { v: 'undefined' };
+  if (Object.is(value, undefined))
+    return { v: 'undefined' };
+  if (Object.is(value, null))
+    return { v: 'null' };
+  if (Object.is(value, NaN))
+    return { v: 'NaN' };
+  if (Object.is(value, Infinity))
+    return { v: 'Infinity' };
+  if (Object.is(value, -Infinity))
+    return { v: '-Infinity' };
+  if (Object.is(value, -0))
+    return { v: '-0' };
+  if (typeof value === 'boolean')
+    return { b: value };
+  if (typeof value === 'number')
+    return { n: value };
+  if (typeof value === 'string')
+    return { s: value };
+  if (isError(value)) {
+    const error = value;
+    if ('captureStackTrace' in global.Error) {
+      // v8
+      return { s: error.stack || '' };
+    }
+    return { s: `${error.name}: ${error.message}\n${error.stack}` };
+  }
+  if (isDate(value))
+    return { d: value.toJSON() };
+  if (isRegExp(value))
+    return { r: { p: value.source, f: value.flags } };
+  if (Array.isArray(value)) {
+    const a = [];
+    visited.add(value);
+    for (let i = 0; i < value.length; ++i)
+      a.push(serializeValue(value[i], handleSerializer, visited));
+    visited.delete(value);
+    return { a };
+  }
+  if (typeof value === 'object') {
+    const o: { k: string, v: SerializedValue }[] = [];
+    visited.add(value);
+    for (const name of Object.keys(value))
+      o.push({ k: name, v: serializeValue(value[name], handleSerializer, visited) });
+    visited.delete(value);
+    return { o };
+  }
+  throw new Error('Unexpected value');
+}
+
+function isRegExp(obj: any): obj is RegExp {
+  return obj instanceof RegExp || Object.prototype.toString.call(obj) === '[object RegExp]';
+}
+
+function isDate(obj: any): obj is Date {
+  return obj instanceof Date || Object.prototype.toString.call(obj) === '[object Date]';
+}
+
+function isError(obj: any): obj is Error {
+  return obj instanceof Error || (obj && obj.__proto__ && obj.__proto__.name === 'Error');
+}
diff --git a/src/rpc/server/electronDispatcher.ts b/src/rpc/server/electronDispatcher.ts
index 0192b563c5..dd70887c54 100644
--- a/src/rpc/server/electronDispatcher.ts
+++ b/src/rpc/server/electronDispatcher.ts
@@ -16,13 +16,12 @@
 
 import { Dispatcher, DispatcherScope, lookupDispatcher } from './dispatcher';
 import { Electron, ElectronApplication, ElectronEvents, ElectronPage } from '../../server/electron';
-import { ElectronApplicationChannel, ElectronApplicationInitializer, PageChannel, JSHandleChannel, ElectronInitializer, ElectronChannel, SerializedArgument, ElectronLaunchParams } from '../channels';
+import { ElectronApplicationChannel, ElectronApplicationInitializer, PageChannel, JSHandleChannel, ElectronInitializer, ElectronChannel, SerializedArgument, ElectronLaunchParams, SerializedValue } from '../channels';
 import { BrowserContextDispatcher } from './browserContextDispatcher';
 import { BrowserContextBase } from '../../browserContext';
 import { PageDispatcher } from './pageDispatcher';
 import { parseArgument, serializeResult } from './jsHandleDispatcher';
 import { createHandle } from './elementHandlerDispatcher';
-import { SerializedValue } from '../../common/utilityScriptSerializers';
 import { envArrayToObject } from '../serializers';
 
 export class ElectronDispatcher extends Dispatcher<Electron, ElectronInitializer> implements ElectronChannel {
diff --git a/src/rpc/server/elementHandlerDispatcher.ts b/src/rpc/server/elementHandlerDispatcher.ts
index 9b88d7c919..9a61f8e073 100644
--- a/src/rpc/server/elementHandlerDispatcher.ts
+++ b/src/rpc/server/elementHandlerDispatcher.ts
@@ -17,11 +17,10 @@
 import { ElementHandle } from '../../dom';
 import * as js from '../../javascript';
 import * as types from '../../types';
-import { ElementHandleChannel, FrameChannel, Binary, SerializedArgument } from '../channels';
+import { ElementHandleChannel, FrameChannel, Binary, SerializedArgument, SerializedValue } from '../channels';
 import { DispatcherScope, lookupNullableDispatcher } from './dispatcher';
 import { JSHandleDispatcher, serializeResult, parseArgument } from './jsHandleDispatcher';
 import { FrameDispatcher } from './frameDispatcher';
-import { SerializedValue } from '../../common/utilityScriptSerializers';
 
 export function createHandle(scope: DispatcherScope, handle: js.JSHandle): JSHandleDispatcher {
   return handle.asElement() ? new ElementHandleDispatcher(scope, handle.asElement()!) : new JSHandleDispatcher(scope, handle);
diff --git a/src/rpc/server/frameDispatcher.ts b/src/rpc/server/frameDispatcher.ts
index 3a6d40f2e5..cdd1c2423c 100644
--- a/src/rpc/server/frameDispatcher.ts
+++ b/src/rpc/server/frameDispatcher.ts
@@ -16,12 +16,11 @@
 
 import { Frame, kAddLifecycleEvent, kRemoveLifecycleEvent, kNavigationEvent, NavigationEvent } from '../../frames';
 import * as types from '../../types';
-import { ElementHandleChannel, FrameChannel, FrameInitializer, JSHandleChannel, ResponseChannel, SerializedArgument, FrameWaitForFunctionParams } from '../channels';
+import { ElementHandleChannel, FrameChannel, FrameInitializer, JSHandleChannel, ResponseChannel, SerializedArgument, FrameWaitForFunctionParams, SerializedValue } from '../channels';
 import { Dispatcher, DispatcherScope, lookupNullableDispatcher, existingDispatcher } from './dispatcher';
 import { convertSelectOptionValues, ElementHandleDispatcher, createHandle, convertInputFiles } from './elementHandlerDispatcher';
 import { parseArgument, serializeResult } from './jsHandleDispatcher';
 import { ResponseDispatcher, RequestDispatcher } from './networkDispatchers';
-import { SerializedValue } from '../../common/utilityScriptSerializers';
 
 export class FrameDispatcher extends Dispatcher<Frame, FrameInitializer> implements FrameChannel {
   private _frame: Frame;
diff --git a/src/rpc/server/jsHandleDispatcher.ts b/src/rpc/server/jsHandleDispatcher.ts
index e82141b483..ef6907a945 100644
--- a/src/rpc/server/jsHandleDispatcher.ts
+++ b/src/rpc/server/jsHandleDispatcher.ts
@@ -15,10 +15,10 @@
  */
 
 import * as js from '../../javascript';
-import { JSHandleChannel, JSHandleInitializer, SerializedArgument } from '../channels';
+import { JSHandleChannel, JSHandleInitializer, SerializedArgument, SerializedValue } from '../channels';
 import { Dispatcher, DispatcherScope } from './dispatcher';
-import { parseEvaluationResultValue, serializeAsCallArgument, SerializedValue } from '../../common/utilityScriptSerializers';
 import { createHandle } from './elementHandlerDispatcher';
+import { parseSerializedValue, serializeValue } from '../serializers';
 
 export class JSHandleDispatcher extends Dispatcher<js.JSHandle, JSHandleInitializer> implements JSHandleChannel {
 
@@ -63,9 +63,9 @@ export class JSHandleDispatcher extends Dispatcher<js.JSHandle, JSHandleInitiali
 // Generic channel parser converts guids to JSHandleDispatchers,
 // and this function takes care of coverting them into underlying JSHandles.
 export function parseArgument(arg: SerializedArgument): any {
-  return parseEvaluationResultValue(arg.value as any, arg.handles.map(arg => (arg as JSHandleDispatcher)._object));
+  return parseSerializedValue(arg.value, arg.handles.map(a => (a as JSHandleDispatcher)._object));
 }
 
 export function serializeResult(arg: any): SerializedValue {
-  return serializeAsCallArgument(arg, value => ({ fallThrough: value }));
+  return serializeValue(arg, value => ({ fallThrough: value }), new Set());
 }
diff --git a/src/rpc/server/pageDispatcher.ts b/src/rpc/server/pageDispatcher.ts
index 50a9e398bf..5b10fa8b9f 100644
--- a/src/rpc/server/pageDispatcher.ts
+++ b/src/rpc/server/pageDispatcher.ts
@@ -20,7 +20,7 @@ import { Frame } from '../../frames';
 import { Request } from '../../network';
 import { Page, Worker } from '../../page';
 import * as types from '../../types';
-import { BindingCallChannel, BindingCallInitializer, ElementHandleChannel, PageChannel, PageInitializer, ResponseChannel, WorkerInitializer, WorkerChannel, JSHandleChannel, Binary, SerializedArgument, PagePdfParams, SerializedError, PageAccessibilitySnapshotResult } from '../channels';
+import { BindingCallChannel, BindingCallInitializer, ElementHandleChannel, PageChannel, PageInitializer, ResponseChannel, WorkerInitializer, WorkerChannel, JSHandleChannel, Binary, SerializedArgument, PagePdfParams, SerializedError, PageAccessibilitySnapshotResult, SerializedValue } from '../channels';
 import { Dispatcher, DispatcherScope, lookupDispatcher, lookupNullableDispatcher } from './dispatcher';
 import { parseError, serializeError, headersArrayToObject, axNodeToProtocol } from '../serializers';
 import { ConsoleMessageDispatcher } from './consoleMessageDispatcher';
@@ -32,7 +32,6 @@ import { serializeResult, parseArgument } from './jsHandleDispatcher';
 import { ElementHandleDispatcher, createHandle } from './elementHandlerDispatcher';
 import { FileChooser } from '../../fileChooser';
 import { CRCoverage } from '../../chromium/crCoverage';
-import { SerializedValue } from '../../common/utilityScriptSerializers';
 
 export class PageDispatcher extends Dispatcher<Page, PageInitializer> implements PageChannel {
   private _page: Page;
diff --git a/utils/generate_channels.js b/utils/generate_channels.js
index e769d29584..c3d84a5cbd 100755
--- a/utils/generate_channels.js
+++ b/utils/generate_channels.js
@@ -51,7 +51,8 @@ function titleCase(name) {
   return name[0].toUpperCase() + name.substring(1);
 }
 
-function inlineType(type, item, indent) {
+function inlineType(item, indent) {
+  let type = item.words[1];
   const array = type.endsWith('[]');
   if (array)
     type = type.substring(0, type.length - 2);
@@ -93,7 +94,7 @@ function properties(item, indent) {
     const optional = name.endsWith('?');
     if (optional)
       name = name.substring(0, name.length - 1);
-    result.push(`${indent}${name}${optional ? '?' : ''}: ${inlineType(prop.words[1], prop, indent)},`);
+    result.push(`${indent}${name}${optional ? '?' : ''}: ${inlineType(prop, indent)},`);
   }
   return result.join('\n');
 }
@@ -140,15 +141,7 @@ for (const item of list) {
 }
 
 for (const item of list) {
-  if (item.words[0] === 'union') {
-    if (item.words.length !== 2)
-      raise(item);
-    result.push(`export type ${item.words[1]} = ${item.list.map(clause => {
-      if (clause.words.length !== 1)
-        raise(clause);
-      return inlineType(clause.words[0], clause, '  ');
-    }).join(' | ')};`);
-  } else if (item.words[0] === 'type') {
+  if (item.words[0] === 'type') {
     if (item.words.length !== 2)
       raise(item);
     result.push(`export type ${item.words[1]} = {`);