commit fef8653c5adcd7c5b7fc2c49ae1a0f6927ddb37f
author zijiehe <zijiehe@chromium.org> Mon Sep 05 15:26:32 2016 -0700
committer Commit bot <commit-bot@chromium.org> Mon Sep 05 22:26:40 2016 +0000
tree 943b7b0e9ccb7d946ea67134b88f0b815dfdb12a
parent f71d298217bd9efd85678fe5632228d4d2b12de2

An early analysis shows in DirectX based capturer, Windows API returns larger
dirty region than the real screen change. A similar behavior may happen on other
platforms with damage notification support. So it's better to have an individual
layer to handle the Differ logic, and remove capturing independent logic out of
each ScreenCapturer* implementation.

So this change does following things,
1. Update differ_block to handle variable height. differ_block_sse2 has been
renamed to differ_vector_sse2.

2. A new ScreenCapturerDifferWrapper implementation to help set
DesktopFrame::updated_region(). It uses an underlying ScreenCapturer to do
the real capture work, and updates the updated region of DesktopFrame returned
from OnCaptureResult function.

3. FakeDesktopCapturer and FakeScreenCapturer to generate controllable
DesktopFrame by using DesktopFrameGenerator and DesktopFramePainter.

4. Test ScreenCapturerDifferWrapper by using FakeScreenCapturer.

After this change, we can eventually remove all Differ logic from
ScreenCapturer* implementations, and fix a potential crash bug in
ScreenCapturerLinux class. It wrongly assumes previous_frame() has a same size
as current_frame(). https://goo.gl/3nSqOC

BUG=633802

TBR=kjellander@webrtc.org

Review-Url: https://codereview.webrtc.org/2202443002
Cr-Commit-Position: refs/heads/master@{#14076}