cc: Skip analysis for narrow layers.

cc/resources/picture_pile_impl.cc

 // Copyright 2012 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 <algorithm>
 #include <limits>
 
 #include "base/debug/trace_event.h"
 #include "cc/base/region.h"
 #include "cc/debug/debug_colors.h"
@@ skipping 358 matching lines @@
   layer_rect.Intersect(gfx::Rect(tiling_.total_size()));
 
   skia::AnalysisCanvas canvas(layer_rect.width(), layer_rect.height());
 
   RasterForAnalysis(&canvas, layer_rect, 1.0f, stats_instrumentation);
 
   analysis->is_solid_color = canvas.GetColorIfSolid(&analysis->solid_color);
   analysis->has_text = canvas.HasText();
 }
 
-PicturePileImpl::Analysis::Analysis()
-    : is_solid_color(false),
-      has_text(false) {
-}
+// Since there are situations when we can skip analysis, the variables have to
+// be set to their safest values. That is, we have to assume that the tile is
+// not solid color. As well, we have to assume that the tile has text so we
+// don't early out incorrectly.
+PicturePileImpl::Analysis::Analysis() : is_solid_color(false), has_text(true) {}
 
 PicturePileImpl::Analysis::~Analysis() {
 }
 
 PicturePileImpl::PixelRefIterator::PixelRefIterator(
     const gfx::Rect& content_rect,
     float contents_scale,
     const PicturePileImpl* picture_pile)
     : picture_pile_(picture_pile),
       layer_rect_(
@@ skipping 49 matching lines @@
        ++it) {
     Picture* picture = it->second.GetPicture();
     if (picture && (processed_pictures.count(picture) == 0)) {
       picture->EmitTraceSnapshot();
       processed_pictures.insert(picture);
     }
   }
 }
 
 }  // namespace cc