Revert 34951 - Combine ViewHostMsg_{Paint,Scroll}Rect into one IPC....

Revert 34951 - Combine ViewHostMsg_{Paint,Scroll}Rect into one IPC.

The combined IPC means that scrolling only requires one transport DIB instead
of two.  Previously, we'd use one in the ScrollRect IPC to pass up the pixels
for the exposed region, and then we'd use a second one in the PaintRect IPC to
pass up the pixels for the updated scroll bar rendering.  Now all paints are
done using a single transport DIB.

Optimize RenderWidgetHostViewWin::OnPaint to only paint the damaged regions.
This means calling GetUpdateRgn and GetRegionData to enumerate the list of
damage rects.  Then only those rects are copied from the backing store.

The same optimization is not done for Linux or Mac yet.

R=brettw
BUG=29591
TEST=none

Review URL: http://codereview.chromium.org/506013

TBR=darin@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=34953

[Robert Sesek, 2009-12-18 15:55:32]

Chromium XP : compile failed. [ stdio stdio_html unit_tests - 2 error(s)
warnings ]
Chromium Linux : compile failed. [ stdio ]
Chromium Linux x64 : compile failed. [ stdio ]
Chromium Builder : compile failed. [ stdio ]
Chromium Mac Builder : update scripts failed. [ stdio ]
Chromium Mac Builder : compile failed. [ stdio ]
Linux Perf : compile failed. [ stdio ]
Modules Linux : compile failed. [ stdio ]
Linux Builder (ChromiumOS) : compile failed. [ stdio ]
Chromium Linux Builder (valgrind) : compile failed. [ stdio ]

distcc[23682] ERROR: compile
/home/chrome-bot/.ccache/render_vie.tmp.codf149.23601.ii on
codf1.jail.google.com:3633/6 failed
/b/slave/chromium-rel-linux/build/src/chrome/browser/renderer_host/test/render_view_host_unittest.cc:
In member function 'virtual void
RenderViewHostTest_BadMessageHandlerRenderWidgetHost_Test::TestBody()':
/b/slave/chromium-rel-linux/build/src/chrome/browser/renderer_host/test/render_view_host_unittest.cc:41:
error: 'ViewHostMsg_PaintRect' has not been declared