cc: Clean up max frames/swaps pending usage.

All output surfaces used by the Renderer and UI should
only need a max swaps pending of 1, especially considering
Surfaces and CompositorTimingHistory don't support
multiple queued frames.

The output suface used by the cc::Display, however, may
have more than 1 swap pending - especially on platforms like
CrOS where the SwapAck is deferred until the buffer is actually
displayed.

This patch:
1) Changes the default max pending frames/swaps from 2 to 1.
2) Changes Blimp to have only 1 pending frame.
3) DCHECKS that all Renderers and UIs have a max swaps pending of 1.
4) Sets the default value in the constructor of
   OutpuSurface::Capabilities, rather than through
   an extra check for zero + init.

BUG=525756
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1435133004

Cr-Commit-Position: refs/heads/master@{#360283}

1 files changed, 1 insertions, 0 deletions

diff --git a/cc/surfaces/surface_display_output_surface_unittest.cc b/cc/surfaces/surface_display_output_surface_unittest.cc
index daabafe..2fedf5a 100644
--- a/cc/surfaces/surface_display_output_surface_unittest.cc
+++ b/cc/surfaces/surface_display_output_surface_unittest.cc
@@ -36,6 +36,7 @@ class FakeOnscreenDisplayClient : public OnscreenDisplayClient {
     // to it now for future reference.
     fake_output_surface_ =
         static_cast<FakeOutputSurface*>(output_surface_.get());
+    fake_output_surface_->set_max_frames_pending(2);
   }
 
   FakeOutputSurface* output_surface() { return fake_output_surface_; }