Add Mojo API for Blink hit testing

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index bee86223c90fd75656e878c23480fbd248942b7f..424f6cd0da8a67d5f27b20ad3036905ac6a90e29 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -64,6 +64,7 @@
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/common/browser_side_navigation_policy.h"
+#include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/test/browser_test_utils.h"
@@ -267,6 +268,14 @@ double GetPageScaleFactor(Shell* shell) {
       .page_scale_factor;
 }
 
+bool callback_received = false;
+int received_frame_id = -2;
+
+void callback(int frame_id) {
+  received_frame_id = frame_id;
+  callback_received = true;
+}
+
 // Helper function that performs a surface hittest.
 void SurfaceHitTestTestHelper(
     Shell* shell,
@@ -324,6 +333,18 @@ void SurfaceHitTestTestHelper(
   child_event.click_count = 1;
   main_frame_monitor.ResetEventReceived();
   child_frame_monitor.ResetEventReceived();
+
+  callback_received = false;
+  root->current_frame_host()->GetFrameInputHandler()->HitTestFrameAt(
+      (gfx::PointF)child_event.PositionInWidget(), base::Bind(&callback));
+  while (!callback_received) {
+    base::RunLoop run_loop;
+    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, run_loop.QuitClosure(), TestTimeouts::tiny_timeout());
+    run_loop.Run();
+  }
+  ASSERT_EQ(4, received_frame_id);
+
   router->RouteMouseEvent(root_view, &child_event, ui::LatencyInfo());
 
   EXPECT_TRUE(child_frame_monitor.EventWasReceived());
@@ -619,11 +640,16 @@ std::string SitePerProcessBrowserTest::DepictFrameTree(FrameTreeNode* node) {
 void SitePerProcessBrowserTest::SetUpCommandLine(
     base::CommandLine* command_line) {
   IsolateAllSitesForTesting(command_line);
+  std::vector<base::StringPiece> enabled_features;
+  std::vector<base::StringPiece> disabled_features;
+  enabled_features.push_back(features::kMojoInputMessages.name);
 #if !defined(OS_ANDROID)
   // TODO(bokan): Needed for scrollability check in
   // FrameOwnerPropertiesPropagationScrolling. crbug.com/662196.
-  feature_list_.InitAndDisableFeature(features::kOverlayScrollbar);
+  disabled_features.push_back(features::kOverlayScrollbar.name);
 #endif
+  feature_list_.InitFromCommandLine(base::JoinString(enabled_features, ","),
+                                    base::JoinString(disabled_features, ","));
 }
 
 void SitePerProcessBrowserTest::SetUpOnMainThread() {