Fix flakiness in DragAndDropBrowserTests

chrome/browser/ui/views/drag_and_drop_interactive_uitest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 #include <initializer_list>
 #include <memory>
 #include <string>
 #include <vector>
 
@@ skipping 677 matching lines @@
     if (response != 42)
       return false;
     observer.Wait();
 
     // |frame| might have been swapped-out during a cross-site navigation,
     // therefore we need to get the current RenderFrameHost to work against
     // going forward.
     frame = GetFrameByName(frame_name);
     DCHECK(frame);
 
-    // Wait until frame contents (e.g. images) have painted (which should happen
-    // in the animation frame that *starts* after the onload event - therefore
-    // we need to wait for 2 animation frames).
-    script = std::string(
-        "requestAnimationFrame(function() {\n"
-        "  requestAnimationFrame(function() {\n"
-        "    domAutomationController.send(43);\n"
-        "  });\n"
-        "});\n");
-    if (!content::ExecuteScriptAndExtractInt(frame, script, &response))
-      return false;
-    if (response != 43)
-      return false;
+    // Wait until frame contents have painted and are ready for hit testing.
+    WaitForChildFrameSurfaceReady(frame);
 
     return true;
   }
 
   content::RenderFrameHost* GetFrameByName(const std::string& name_to_find) {
     content::RenderFrameHost* result = nullptr;
     for (content::RenderFrameHost* rfh : web_contents()->GetAllFrames()) {
       if (rfh->GetFrameName() == name_to_find) {
         if (result) {
           ADD_FAILURE() << "More than one frame named "
@@ skipping 110 matching lines @@
               location_inside_web_contents);
     EXPECT_EQ(ui::DragDropTypes::DRAG_COPY, operation);
   }
 
   // Try to leave everything in a clean state.
   SimulateMouseUp();
 }
 
 // There is no known way to execute test-controlled tasks during
 // a drag-and-drop loop run by Windows OS.
-// Flaky on Linux. crbug.com/704603

[alexmos, 2017/03/31 21:57:54]

Since you're reenabling this, also reference this bug in the description?

[kenrb, 2017/04/03 17:28:29]

Done.

-#if defined(OS_WIN) || defined(OS_LINUX)
+#if defined(OS_WIN)
 #define MAYBE_DragImageBetweenFrames DISABLED_DragImageBetweenFrames
 #else
 #define MAYBE_DragImageBetweenFrames DragImageBetweenFrames
 #endif
 
 // Data that needs to be shared across multiple test steps below
 // (i.e. across DragImageBetweenFrames_Step2 and DragImageBetweenFrames_Step3).
 struct DragAndDropBrowserTest::DragImageBetweenFrames_TestState {
   DOMDragEventVerifier expected_dom_event_data;
   std::unique_ptr<DOMDragEventWaiter> dragstart_event_waiter;
@@ skipping 428 matching lines @@
 // of a drag operation, and cross-site drags should be allowed across a
 // navigation.
 
 INSTANTIATE_TEST_CASE_P(
     SameSiteSubframe, DragAndDropBrowserTest, ::testing::Values(false));
 
 INSTANTIATE_TEST_CASE_P(
     CrossSiteSubframe, DragAndDropBrowserTest, ::testing::Values(true));
 
 }  // namespace chrome