Plumb PaintImage for the img.decode instead of SkImage.

cc/tiles/decoded_image_tracker_unittest.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 <vector>
 
 #include "base/bind.h"
 #include "cc/tiles/decoded_image_tracker.h"
 #include "cc/tiles/image_controller.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 38 matching lines @@
   }
 
  private:
   TestImageController image_controller_;
   DecodedImageTracker decoded_image_tracker_;
 };
 
 TEST_F(DecodedImageTrackerTest, QueueImageLocksImages) {
   bool locked = false;
   decoded_image_tracker()->QueueImageDecode(
-      nullptr, base::Bind([](bool* locked, bool success) { *locked = true; },
-                          base::Unretained(&locked)));
+      PaintImage(),
+      base::Bind([](bool* locked, bool success) { *locked = true; },
+                 base::Unretained(&locked)));
   EXPECT_TRUE(locked);
   EXPECT_EQ(1u, image_controller()->num_locked_images());
 }
 
 TEST_F(DecodedImageTrackerTest, NotifyFrameFinishedUnlocksImages) {
   bool locked = false;
   decoded_image_tracker()->QueueImageDecode(
-      nullptr, base::Bind([](bool* locked, bool success) { *locked = true; },
-                          base::Unretained(&locked)));
+      PaintImage(),
+      base::Bind([](bool* locked, bool success) { *locked = true; },
+                 base::Unretained(&locked)));
   EXPECT_TRUE(locked);
   EXPECT_EQ(1u, image_controller()->num_locked_images());
 
   decoded_image_tracker()->NotifyFrameFinished();
   EXPECT_EQ(1u, image_controller()->num_locked_images());
 
   locked = false;
   decoded_image_tracker()->QueueImageDecode(
-      nullptr, base::Bind([](bool* locked, bool success) { *locked = true; },
-                          base::Unretained(&locked)));
+      PaintImage(),
+      base::Bind([](bool* locked, bool success) { *locked = true; },
+                 base::Unretained(&locked)));
   EXPECT_TRUE(locked);
   EXPECT_EQ(2u, image_controller()->num_locked_images());
 
   decoded_image_tracker()->NotifyFrameFinished();
   EXPECT_EQ(1u, image_controller()->num_locked_images());
 
   decoded_image_tracker()->NotifyFrameFinished();
   EXPECT_EQ(0u, image_controller()->num_locked_images());
 }
 
 }  // namespace cc