Reland: cc: Fix size_t to int truncations in layers/ output/ playback/ quads/

cc/output/gl_renderer.cc

 // Copyright 2010 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 "cc/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/math_util.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/copy_output_request.h"
@@ skipping 2200 matching lines @@
     gl_->Uniform4fv(draw_cache_.background_color_location, 1,
                     background_color.data);
   }
 
   gl_->Uniform1fv(
       static_cast<int>(draw_cache_.vertex_opacity_location),
       static_cast<int>(draw_cache_.vertex_opacity_data.size()),
       static_cast<float*>(&draw_cache_.vertex_opacity_data.front()));
 
   // Draw the quads!
-  gl_->DrawElements(GL_TRIANGLES, 6 * draw_cache_.matrix_data.size(),
+  gl_->DrawElements(GL_TRIANGLES,
+                    6 * base::checked_cast<int>(draw_cache_.matrix_data.size()),

[vmpstr, 2015/06/05 01:03:00]

This is the only checked_cast that I'm using, most other places are
saturated_cast. Let me know if this should change. The code around this is
mostly static_casting everything...

[jschuh, 2015/06/05 14:08:24]

Yeah, it looks like the other locations should be using checked or saturated
cast, but that's fine for a follow on.

[danakj, 2015/06/05 18:22:29]

matrix_data.size() is at most 8 (line 2299). Having a CHECK compiled in here
seems wasteful, and this code is running every frame. I think this should be
DCHECK and static_cast IMO.

wtb base::dchecked_cast heh.

[vmpstr, 2015/06/05 19:27:33]

Ok, I changed this to a DCHECK. I think if this is to be fixed, we should just
do it in one pass for all instances of static_cast in gl_renderer.cc

                     GL_UNSIGNED_SHORT, 0);
 
   // Clear the cache.
   draw_cache_.program_id = -1;
   draw_cache_.uv_xform_data.resize(0);
   draw_cache_.vertex_opacity_data.resize(0);
   draw_cache_.matrix_data.resize(0);
 
   // If we had a clipped binding, prepare the shared binding for the
   // next inserts.
@@ skipping 1260 matching lines @@
     context_support_->ScheduleOverlayPlane(
         overlay.plane_z_order,
         overlay.transform,
         pending_overlay_resources_.back()->texture_id(),
         ToNearestRect(overlay.display_rect),
         overlay.uv_rect);
   }
 }
 
 }  // namespace cc