Round IOSurface sizes to 64 pixels for filter effects.

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 48611c498189b0050a4856998c214834d509a370..c1f73f82aaaf4fcb5bc5459ce1a16c426d99e82c 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -3942,7 +3942,29 @@ void GLRenderer::CopyRenderPassDrawQuadToOverlayResource(
   // |params.dst_rect| now contain values that reflect a potentially increased
   // size quad.
   gfx::RectF updated_dst_rect = params.dst_rect;
-  *new_bounds = updated_dst_rect;
+
+  // Round the size of the IOSurface to a multiple of 64 pixels. This reduces
+  // memory fragmentation. https://crbug.com/146070. This also allows IOSurfaces
+  // to be more easily reused during a resize operation.
+  uint32_t iosurface_multiple = 64;

[ccameron, 2016/08/15 18:37:06]

May be more concise to do
  updated_dst_rest.set_width(
      MathUtil::UncheckedRoundUp(updated_dst_rest.width(),
      iosurface_multiple));
and same for height, from
https://cs.chromium.org/chromium/src/cc/base/math_util.h?rcl=1471252828&l=112;

[erikchen, 2016/08/15 19:31:57]

Done, although we can't change updated_dst_rect, since it's parameter are still
relevant for setting the viewport.

+  uint32_t iosurface_width = updated_dst_rect.width();
+  if (iosurface_width % iosurface_multiple != 0) {
+    iosurface_width -= iosurface_width % iosurface_multiple;
+    iosurface_width += iosurface_multiple;
+  }
+
+  uint32_t iosurface_height = updated_dst_rect.height();
+  if (iosurface_height % iosurface_multiple != 0) {
+    iosurface_height -= iosurface_height % iosurface_multiple;
+    iosurface_height += iosurface_multiple;
+  }
+
+  *resource = overlay_resource_pool_->AcquireResource(
+      gfx::Size(iosurface_width, iosurface_height), ResourceFormat::RGBA_8888,
+      output_surface_->device_color_space());
+  *new_bounds =
+      gfx::RectF(updated_dst_rect.x(), updated_dst_rect.y(),
+                 (*resource)->size().width(), (*resource)->size().height());
 
   // Calculate new projection and window matrices for a minimally sized viewport
   // using InitializeViewport(). This requires creating a dummy DrawingFrame.
@@ -3982,9 +4004,6 @@ void GLRenderer::CopyRenderPassDrawQuadToOverlayResource(
   }
 
   // Establish destination texture.
-  *resource = overlay_resource_pool_->AcquireResource(
-      gfx::Size(updated_dst_rect.width(), updated_dst_rect.height()),
-      ResourceFormat::RGBA_8888, output_surface_->device_color_space());
   ResourceProvider::ScopedWriteLockGL destination(resource_provider_,
                                                   (*resource)->id(), false);
   GLuint temp_fbo;