[android_webview] Use a fraction to calculate scroll offset.

cc/layers/layer_impl_unittest.cc

 // Copyright 2011 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/layer_impl.h"
 
 #include "cc/output/filter_operation.h"
 #include "cc/output/filter_operations.h"
 #include "cc/test/fake_impl_proxy.h"
 #include "cc/test/fake_layer_tree_host_impl.h"
@@ skipping 373 matching lines @@
   layer()->ScrollBy(gfx::Vector2dF(100, -100));
   EXPECT_VECTOR_EQ(gfx::Vector2dF(50, 0), layer()->TotalScrollOffset());
 
   EXPECT_VECTOR_EQ(layer()->ScrollDelta() + scroll_offset,
                    layer()->TotalScrollOffset());
   EXPECT_VECTOR_EQ(scroll_offset, layer()->scroll_offset());
 }
 
 class ScrollDelegateIgnore : public LayerScrollOffsetDelegate {
  public:
+  virtual void SetMaxScrollOffset(gfx::Vector2dF max_scroll_offset) OVERRIDE {}
   virtual void SetTotalScrollOffset(gfx::Vector2dF new_value) OVERRIDE {}
   virtual gfx::Vector2dF GetTotalScrollOffset() OVERRIDE {
     return fixed_offset_;
   }
 
   void set_fixed_offset(gfx::Vector2dF fixed_offset) {
     fixed_offset_ = fixed_offset;
   }
 
  private:
@@ skipping 30 matching lines @@
 
   gfx::Vector2dF scroll_delta(1, 1);
   layer()->ScrollBy(scroll_delta);
 
   EXPECT_VECTOR_EQ(fixed_offset + scroll_delta, layer()->TotalScrollOffset());
   EXPECT_VECTOR_EQ(scroll_offset, layer()->scroll_offset());
 }
 
 class ScrollDelegateAccept : public LayerScrollOffsetDelegate {
  public:
+  virtual void SetMaxScrollOffset(gfx::Vector2dF max_scroll_offset) OVERRIDE {}
   virtual void SetTotalScrollOffset(gfx::Vector2dF new_value) OVERRIDE {
     current_offset_ = new_value;
   }
   virtual gfx::Vector2dF GetTotalScrollOffset() OVERRIDE {
     return current_offset_;
   }
 
  private:
   gfx::Vector2dF current_offset_;
 };
@@ skipping 99 matching lines @@
 
   layer()->ApplySentScrollDeltasFromAbortedCommit();
 
   EXPECT_VECTOR_EQ(scroll_offset + scroll_delta, layer()->TotalScrollOffset());
   EXPECT_VECTOR_EQ(scroll_offset + sent_scroll_delta, layer()->scroll_offset());
   EXPECT_VECTOR_EQ(gfx::Vector2d(), layer()->sent_scroll_delta());
 }
 
 }  // namespace
 }  // namespace cc