cc: Change max_tiles_for_interest_rect to be screen pixels padding.

cc/layers/picture_layer_impl_unittest.cc

 // Copyright 2013 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/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <utility>
@@ skipping 4734 matching lines @@
 
   SetupPendingTreeWithFixedTileSize(active_pile, tile_size, Region());
 
   ActivateTree();
   EXPECT_TRUE(active_layer_->HighResTiling()->has_tiles());
 
   host_impl_.SetExternalDrawConstraints(
       gfx::Transform(),              // transform
       gfx::Rect(),                   // clip
       gfx::Rect(),                   // viewport
-      gfx::Rect(0, 1000, 100, 100),  // viewport_rect_for_tile_priority
+      gfx::Rect(0, 5000, 100, 100),  // viewport_rect_for_tile_priority
       gfx::Transform(),              // transform_for_tile_priority
       false);
 
   SetupPendingTreeWithFixedTileSize(pending_pile, tile_size, gfx::Rect());
 
   EXPECT_FALSE(pending_layer_->HighResTiling()->has_tiles());
   EXPECT_TRUE(pending_layer_->HighResTiling()->live_tiles_rect().IsEmpty());
   ActivateTree();
   EXPECT_FALSE(active_layer_->HighResTiling()->has_tiles());
   EXPECT_TRUE(active_layer_->HighResTiling()->live_tiles_rect().IsEmpty());
@@ skipping 227 matching lines @@
   // Zoom out to exactly the low res factor so that the previous high res
   // would be equal to the current low res (if it were possible to have one).
   float zoomed = page_scale / low_res_factor;
   SetContentsScaleOnBothLayers(zoomed, 1.0f, zoomed, 1.0f, 0.f, false);
   EXPECT_EQ(1u, pending_layer_->num_tilings());
   EXPECT_EQ(zoomed, pending_layer_->tilings()->tiling_at(0)->contents_scale());
 }
 
 }  // namespace
 }  // namespace cc