Add Emulation.setNavigatorPlatform

Sometimes in headless we need to emulate mobile devices including changing
navigator.platform. This DevTools command achieves that.

Bug: 
Change-Id: Id305db9fa595d527225c2e19bb269cb60f29110f
Reviewed-on: https://chromium-review.googlesource.com/603715
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501225}

third_party/WebKit/LayoutTests/inspector-protocol/emulation/set-navigator-platform-expected.txt

+Tests that navigator.platform can be overridden.
+navigator.platform = TestPlatform
+

third_party/WebKit/LayoutTests/inspector-protocol/emulation/set-navigator-platform.js

+(async function(testRunner) {
+  var {page, session, dp} = await testRunner.startBlank('Tests that navigator.platform can be overridden.');
+
+  await dp.Emulation.setNavigatorOverrides({ platform: 'TestPlatform' });
+  var result = await dp.Runtime.evaluate({ expression: 'navigator.platform' });
+  testRunner.log('navigator.platform = ' + result.result.result.value);
+  testRunner.completeTest();
+})

third_party/WebKit/Source/core/frame/Navigator.cpp

@@ -59,6 +59,14 @@ String Navigator::vendorSub() const {
   return "";
 }
 
+String Navigator::platform() const {
+  if (GetFrame() &&
+      !GetFrame()->GetSettings()->GetNavigatorPlatformOverride().IsEmpty()) {
+    return GetFrame()->GetSettings()->GetNavigatorPlatformOverride();
+  }
+  return NavigatorID::platform();
+}
+
 String Navigator::userAgent() const {
   // If the frame is already detached it no longer has a meaningful useragent.
   if (!GetFrame() || !GetFrame()->GetPage())

third_party/WebKit/Source/core/frame/Navigator.h

@@ -57,6 +57,7 @@ class CORE_EXPORT Navigator final : public GarbageCollected<Navigator>,
   String vendor() const;
   String vendorSub() const;
 
+  String platform() const override;
   String userAgent() const override;
 
   // NavigatorLanguage

third_party/WebKit/Source/core/frame/NavigatorID.cpp

@@ -55,7 +55,7 @@ String NavigatorID::appVersion() {
   return agent.Substring(agent.find('/') + 1);
 }
 
-String NavigatorID::platform() {
+String NavigatorID::platform() const {
 #if defined(OS_MACOSX)
   // Match Safari and Mozilla on Mac x86.
   return "MacIntel";

third_party/WebKit/Source/core/frame/NavigatorID.h

@@ -41,7 +41,7 @@ class CORE_EXPORT NavigatorID {
   String appCodeName();
   String appName();
   String appVersion();
-  String platform();
+  virtual String platform() const;
   String product();
   virtual String userAgent() const = 0;
 };

third_party/WebKit/Source/core/frame/Settings.json5

@@ -971,5 +971,9 @@
       name: "forceDisplayList2dCanvasEnabled",
       initial: false,
     },
+    {
+      name: "navigatorPlatformOverride",
+      type: "String",
+    },
   ],
 }

third_party/WebKit/Source/core/inspector/InspectorEmulationAgent.cpp

@@ -31,6 +31,7 @@ static const char kMaxTouchPoints[] = "maxTouchPoints";
 static const char kEmulatedMedia[] = "emulatedMedia";
 static const char kDefaultBackgroundColorOverrideRGBA[] =
     "defaultBackgroundColorOverrideRGBA";
+static const char kNavigatorPlatform[] = "navigatorPlatform";
 }
 
 InspectorEmulationAgent* InspectorEmulationAgent::Create(
@@ -72,6 +73,10 @@ void InspectorEmulationAgent::Restore() {
           Maybe<protocol::DOM::RGBA>(std::move(rgba)));
     }
   }
+  String navigator_platform;
+  state_->getString(EmulationAgentState::kNavigatorPlatform,
+                    &navigator_platform);
+  setNavigatorOverrides(navigator_platform);
 }
 
 Response InspectorEmulationAgent::disable() {
@@ -84,6 +89,7 @@ Response InspectorEmulationAgent::disable() {
     web_local_frame_->View()->Scheduler()->RemoveVirtualTimeObserver(this);
     virtual_time_observer_registered_ = false;
   }
+  setNavigatorOverrides(String());
   return Response::OK();
 }
 
@@ -160,6 +166,14 @@ Response InspectorEmulationAgent::setVirtualTimePolicy(const String& policy,
   return Response::OK();
 }
 
+Response InspectorEmulationAgent::setNavigatorOverrides(
+    const String& platform) {
+  state_->setString(EmulationAgentState::kNavigatorPlatform, platform);
+  GetWebViewImpl()->GetPage()->GetSettings().SetNavigatorPlatformOverride(
+      platform);
+  return Response::OK();
+}
+
 void InspectorEmulationAgent::VirtualTimeBudgetExpired() {
   web_local_frame_->View()->Scheduler()->SetVirtualTimePolicy(
       WebViewScheduler::VirtualTimePolicy::PAUSE);

third_party/WebKit/Source/core/inspector/InspectorEmulationAgent.h

@@ -50,6 +50,7 @@ class CORE_EXPORT InspectorEmulationAgent final
   protocol::Response setVirtualTimePolicy(
       const String& policy,
       protocol::Maybe<int> virtual_time_budget_ms) override;
+  protocol::Response setNavigatorOverrides(const String& platform) override;
   protocol::Response setDefaultBackgroundColorOverride(
       protocol::Maybe<protocol::DOM::RGBA>) override;
 

third_party/WebKit/Source/core/inspector/browser_protocol.json

@@ -1081,6 +1081,14 @@
                 ],
                 "experimental": true
             },
+            {
+                "name": "setNavigatorOverrides",
+                "description": "Overrides value returned by the javascript navigator object.",
+                "parameters": [
+                    { "name": "platform", "type": "string", "description": "The platform navigator.platform should return." }
+                ],
+                "experimental": true
+            },
             {
                 "name": "setDefaultBackgroundColorOverride",
                 "description": "Sets or clears an override of the default background color of the frame. This override is used if the content does not specify one.",

third_party/WebKit/Source/core/inspector/inspector_protocol_config.json

@@ -90,7 +90,7 @@
             {
                 "domain": "Emulation",
                 "include": ["forceViewport", "resetViewport", "resetPageScaleFactor", "setPageScaleFactor", "setScriptExecutionDisabled", "setTouchEmulationEnabled",
-                            "setEmulatedMedia", "setCPUThrottlingRate", "setVirtualTimePolicy", "setDefaultBackgroundColorOverride"],
+                            "setEmulatedMedia", "setCPUThrottlingRate", "setVirtualTimePolicy", "setNavigatorOverrides", "setDefaultBackgroundColorOverride"],
                 "include_events": ["virtualTimeBudgetExpired", "virtualTimePaused"]
             },
             {