[Media UX] Enable the pixel by pixel comparison test for Mac OS.

1. Tested on Mac and verify everything works as expected.
2. Removed the unnecessary call of GetNativeWindow().
3. The RGB for GPU enabled and GPU disabled test images is slightly different. Additional check is needed.

Bug: 898230
Change-Id: I85bf2450862361572597632159de60db6abf2c22
Reviewed-on: https://chromium-review.googlesource.com/c/1307062Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: Clifford Cheng <cliffordcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606552}

chrome/browser/picture_in_picture/picture_in_picture_window_controller_browsertest.cc

@@ -12,7 +12,6 @@
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
-#include "chrome/browser/ui/views/overlay/overlay_window_views.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "components/viz/common/frame_sinks/copy_output_request.h"
@@ -190,7 +189,7 @@ IN_PROC_BROWSER_TEST_F(PictureInPictureWindowControllerBrowserTest,
   EXPECT_TRUE(window_controller()->GetWindowForTesting()->IsVisible());
 }
 
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+#if (defined(OS_MACOSX) || defined(OS_LINUX)) && !defined(OS_CHROMEOS)
 class PictureInPicturePixelComparisonBrowserTest
     : public PictureInPictureWindowControllerBrowserTest {
  public:
@@ -233,12 +232,23 @@ class PictureInPicturePixelComparisonBrowserTest
             base::BindOnce(
                 &PictureInPicturePixelComparisonBrowserTest::ReadbackResult,
                 base::Unretained(this), run_loop.QuitClosure()));
-    overlay_window_views->GetNativeWindow()->layer()->RequestCopyOfOutput(
-        std::move(request));
+    overlay_window_views->GetLayer()->RequestCopyOfOutput(std::move(request));
+    run_loop.Run();
+  }
+
+  void Wait(base::TimeDelta timeout) {
+    base::RunLoop run_loop;
+    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, run_loop.QuitClosure(), timeout);
     run_loop.Run();
   }
 
   bool CompareImages(const SkBitmap& actual_bmp) {
+    // Allowable error and thresholds because of small color shift by
+    // video to image conversion and GPU issues.
+    const int allowable_error = 2;
+    const unsigned high_threshold = 0xff - allowable_error;
+    const unsigned low_threshold = 0x00 + allowable_error;
     // Number of pixels with an error
     int error_pixels_count = 0;
     gfx::Rect error_bounding_rect;
@@ -246,12 +256,12 @@ class PictureInPicturePixelComparisonBrowserTest
     for (int x = 0; x < actual_bmp.width(); ++x) {
       for (int y = 0; y < actual_bmp.height(); ++y) {
         SkColor actual_color = actual_bmp.getColor(x, y);
-        // Check color is Yellow. The difference is caused by video conversion.
+        // Check color is Yellow and is within the tolerance range.
         // TODO(cliffordcheng): Compare with an expected image instead of just
         // checking pixel RGB color.
-        if (SkColorGetR(actual_color) != 254 &&
-            SkColorGetG(actual_color) != 253 &&
-            SkColorGetB(actual_color) != 0) {
+        if (SkColorGetR(actual_color) < high_threshold &&
+            SkColorGetG(actual_color) < high_threshold &&
+            SkColorGetB(actual_color) > low_threshold) {
           ++error_pixels_count;
           error_bounding_rect.Union(gfx::Rect(x, y, 1, 1));
         }
@@ -271,8 +281,7 @@ class PictureInPicturePixelComparisonBrowserTest
   std::unique_ptr<SkBitmap> result_bitmap_;
 };
 
-// TODO(cliffordcheng): enable this tests on other platforms when
-// Windows and Mac capture screen problem is solved.
+// TODO(cliffordcheng): enable on Windows when compile errors are resolved.
 // Plays a video and then trigger Picture-in-Picture. Grabs a screenshot of
 // Picture-in-Picture window and verifies it's as expected.
 IN_PROC_BROWSER_TEST_F(PictureInPicturePixelComparisonBrowserTest, VideoPlay) {
@@ -320,7 +329,7 @@ IN_PROC_BROWSER_TEST_F(PictureInPicturePixelComparisonBrowserTest, VideoPlay) {
   ASSERT_TRUE(SaveBitmap(test_image_path, GetResultBitmap()));
   EXPECT_TRUE(CompareImages(GetResultBitmap()));
 }
-#endif  // defined(OS_LINUX) && !defined(OS_CHROMEOS)
+#endif  // (defined(OS_MACOSX) || defined(OS_LINUX)) && !defined(OS_CHROMEOS)
 
 // Tests that when an active WebContents accurately tracks whether a video
 // is in Picture-in-Picture.