DevTools: introduce Page.close() protocol method

This patch adds new experimental Page.close() protocol method
that closes the page, running page's beforeunload hooks.

R=dgozman

Change-Id: I4c091bb150e8d88e99c94920e92b1bdcf0ccb234
Reviewed-on: https://chromium-review.googlesource.com/1014676Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Andrey Lushnikov <lushnikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552071}

content/browser/devtools/protocol/page_handler.cc

@@ -395,6 +395,14 @@ Response PageHandler::Crash() {
   return Response::FallThrough();
 }
 
+Response PageHandler::Close() {
+  WebContentsImpl* web_contents = GetWebContents();
+  if (!web_contents)
+    return Response::Error("Not attached to a page");
+  web_contents->DispatchBeforeUnload();
+  return Response::OK();
+}
+
 Response PageHandler::Reload(Maybe<bool> bypassCache,
                              Maybe<std::string> script_to_evaluate_on_load) {
   WebContentsImpl* web_contents = GetWebContents();

content/browser/devtools/protocol/page_handler.h

@@ -95,6 +95,7 @@ class PageHandler : public DevToolsDomainHandler,
   Response Disable() override;
 
   Response Crash() override;
+  Response Close() override;
   Response Reload(Maybe<bool> bypassCache,
                   Maybe<std::string> script_to_evaluate_on_load) override;
   void Navigate(const std::string& url,

content/browser/devtools/protocol_config.json

@@ -48,7 +48,7 @@
                 "domain": "Page",
                 "include": ["enable", "disable", "reload", "navigate", "stopLoading", "getNavigationHistory", "navigateToHistoryEntry", "captureScreenshot",
                     "startScreencast", "stopScreencast", "screencastFrameAck", "handleJavaScriptDialog", "setColorPickerEnabled", "requestAppBanner",
-                    "printToPDF", "bringToFront", "setDownloadBehavior", "getAppManifest", "crash"],
+                    "printToPDF", "bringToFront", "setDownloadBehavior", "getAppManifest", "crash", "close"],
                 "include_events": ["colorPicked", "interstitialShown", "interstitialHidden", "javascriptDialogOpening", "javascriptDialogClosed", "screencastVisibilityChanged", "screencastFrame"],
                 "async": ["captureScreenshot", "printToPDF", "navigate", "getAppManifest"]
             },

third_party/WebKit/LayoutTests/inspector-protocol/page/page-close-expected.txt

+Tests that page.requestClose method runs beforeunload hooks.
+SUCCESS!
+

third_party/WebKit/LayoutTests/inspector-protocol/page/page-close.js

+(async function(testRunner) {
+  var {page, session, dp} = await testRunner.startBlank('Tests that page.requestClose method runs beforeunload hooks.');
+
+  await dp.Runtime.enable();
+  await session.evaluate(() => {
+    window.addEventListener('beforeunload', function (event) {
+      console.log('YES');
+    }, false);
+  });
+
+  dp.Page.close();
+
+  // Console message should be emitted from-inside the beforeunload handler.
+  await dp.Runtime.onceConsoleAPICalled();
+  testRunner.log('SUCCESS!');
+  testRunner.completeTest();
+})

third_party/blink/renderer/core/inspector/browser_protocol.pdl

@@ -4893,6 +4893,9 @@ domain Page
   # Crashes renderer on the IO thread, generates minidumps.
   experimental command crash
 
+  # Tries to close page, running its beforeunload hooks, if any.
+  experimental command close
+
   # Stops sending each frame in the `screencastFrame`.
   experimental command stopScreencast
 

third_party/blink/renderer/core/inspector/inspector_protocol_config.json

@@ -80,7 +80,7 @@
             {
                 "domain": "Page",
                 "exclude": ["getNavigationHistory", "navigateToHistoryEntry", "captureScreenshot", "screencastFrameAck", "handleJavaScriptDialog", "setColorPickerEnabled",
-                            "getAppManifest", "requestAppBanner", "setControlNavigations", "processNavigation", "printToPDF", "bringToFront", "setDownloadBehavior", "navigate", "crash"],
+                            "getAppManifest", "requestAppBanner", "setControlNavigations", "processNavigation", "printToPDF", "bringToFront", "setDownloadBehavior", "navigate", "crash", "close"],
                 "async": ["getResourceContent", "searchInResource"],
                 "exclude_events": ["screencastFrame", "screencastVisibilityChanged", "colorPicked", "interstitialShown", "interstitialHidden", "javascriptDialogOpening", "javascriptDialogClosed", "navigationRequested"]
             },