Fix flakiness in AccessibilityHighlightManagerTest and re-enable.

chrome/browser/chromeos/accessibility/accessibility_highlight_manager_interactive_uitest.cc

 // Copyright (c) 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 "chrome/browser/chromeos/accessibility/accessibility_highlight_manager.h"
 
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/run_loop.h"
@@ skipping 106 matching lines @@
   SkColor average_diff_color() { return average_diff_color_; }
 
  private:
   void GotSnapshot(const gfx::Image& image) {
     image_ = image;
     content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
                                      run_loop_quitter_);
   }
 
   void Capture(const gfx::Rect& bounds) {
-    aura::Window* window = ash::Shell::GetPrimaryRootWindow();
-    ui::GrabWindowSnapshotAndScaleAsync(
-        window, bounds, bounds.size(),
-        content::BrowserThread::GetBlockingPool(),
-        base::Bind(&AccessibilityHighlightManagerTest::GotSnapshot, this));
-    base::RunLoop run_loop;
-    run_loop_quitter_ = run_loop.QuitClosure();
-    run_loop.Run();
+    // Occasionally we don't get any pixels the first try.
+    // Keep trying until we get the correct size bitmap and
+    // the first pixel is not transparent.
+    while (true) {
+      aura::Window* window = ash::Shell::GetPrimaryRootWindow();
+      ui::GrabWindowSnapshotAndScaleAsync(
+          window, bounds, bounds.size(),
+          content::BrowserThread::GetBlockingPool(),
+          base::Bind(&AccessibilityHighlightManagerTest::GotSnapshot, this));
+      base::RunLoop run_loop;
+      run_loop_quitter_ = run_loop.QuitClosure();
+      run_loop.Run();
+      SkBitmap bitmap;
+      image_.AsBitmap().deepCopyTo(&bitmap);

[xiyuan, 2016/06/21 19:19:37]

nit: Is this copy necessary? Can we just use image_.AsBitmap() directly?

[dmazzoni, 2016/06/21 19:59:06]

Good idea, done.

+      SkAutoLockPixels lock(bitmap);
+      if (bitmap.width() != bounds.width() ||
+          bitmap.height() != bounds.height()) {
+        LOG(INFO) << "Bitmap not correct size, trying to capture again";
+        continue;
+      }
+      if (255 == SkColorGetA(bitmap.getColor(0, 0))) {
+        LOG(INFO) << "Bitmap is transparent, trying to capture again";
+        break;
+      }
+    }
   }
 
   base::Closure run_loop_quitter_;
   gfx::Image image_;
   SkBitmap before_bmp_;
   SkBitmap after_bmp_;
   int diff_count_ = 0;
   SkColor average_diff_color_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(AccessibilityHighlightManagerTest);
 };
 
-// Flaky. http://crbug.com/621306
 IN_PROC_BROWSER_TEST_F(AccessibilityHighlightManagerTest,
-                       DISABLED_TestCaretRingDrawsBluePixels) {
+                       TestCaretRingDrawsBluePixels) {
   gfx::Rect capture_bounds(200, 300, 100, 100);
   gfx::Rect caret_bounds(230, 330, 1, 25);
 
   CaptureBeforeImage(capture_bounds);
 
   TestAccessibilityHighlightManager manager;
   manager.HighlightCaret(true);
   MockTextInputClient text_input_client;
   text_input_client.SetCaretBounds(caret_bounds);
   manager.OnCaretBoundsChanged(&text_input_client);
 
   CaptureAfterImage(capture_bounds);
   ComputeImageStats();
 
   // This is a smoke test to assert that something is drawn in the right
   // part of the screen of approximately the right size and color.
   // There's deliberately some tolerance for tiny errors.
   EXPECT_NEAR(1487, diff_count(), 50);
   EXPECT_NEAR(175, SkColorGetR(average_diff_color()), 5);
   EXPECT_NEAR(175, SkColorGetG(average_diff_color()), 5);
   EXPECT_NEAR(255, SkColorGetB(average_diff_color()), 5);
 }
 
-// Flaky. http://crbug.com/621306
 IN_PROC_BROWSER_TEST_F(AccessibilityHighlightManagerTest,
-                       DISABLED_TestCursorRingDrawsRedPixels) {
+                       TestCursorRingDrawsRedPixels) {
   gfx::Rect capture_bounds(200, 300, 100, 100);
   gfx::Point cursor_point(250, 350);
 
   CaptureBeforeImage(capture_bounds);
 
   TestAccessibilityHighlightManager manager;
   manager.HighlightCursor(true);
   ui::MouseEvent mouse_move(ui::ET_MOUSE_MOVED, cursor_point, cursor_point,
                             ui::EventTimeForNow(), 0, 0);
   manager.OnMouseEvent(&mouse_move);
   CaptureAfterImage(capture_bounds);
   ComputeImageStats();
 
   // This is a smoke test to assert that something is drawn in the right
   // part of the screen of approximately the right size and color.
   // There's deliberately some tolerance for tiny errors.
   EXPECT_NEAR(1521, diff_count(), 50);
   EXPECT_NEAR(255, SkColorGetR(average_diff_color()), 5);
   EXPECT_NEAR(176, SkColorGetG(average_diff_color()), 5);
   EXPECT_NEAR(176, SkColorGetB(average_diff_color()), 5);
 }
 
-// Flaky. http://crbug.com/621306
 IN_PROC_BROWSER_TEST_F(AccessibilityHighlightManagerTest,
-                       DISABLED_TestFocusRingDrawsOrangePixels) {
+                       TestFocusRingDrawsOrangePixels) {
   gfx::Rect capture_bounds(200, 300, 100, 100);
   gfx::Rect focus_bounds(230, 330, 40, 40);
 
   CaptureBeforeImage(capture_bounds);
 
   TestAccessibilityHighlightManager manager;
   manager.HighlightFocus(true);
   content::FocusedNodeDetails details{false, focus_bounds};
   manager.Observe(content::NOTIFICATION_FOCUS_CHANGED_IN_PAGE,
                   content::Source<AccessibilityHighlightManagerTest>(this),
                   content::Details<content::FocusedNodeDetails>(&details));
   CaptureAfterImage(capture_bounds);
   ComputeImageStats();
 
   // This is a smoke test to assert that something is drawn in the right
   // part of the screen of approximately the right size and color.
   // There's deliberately some tolerance for tiny errors.
   EXPECT_NEAR(1608, diff_count(), 50);
   EXPECT_NEAR(255, SkColorGetR(average_diff_color()), 5);
   EXPECT_NEAR(201, SkColorGetG(average_diff_color()), 5);
   EXPECT_NEAR(152, SkColorGetB(average_diff_color()), 5);
 }
 
 }  // namespace chromeos