[android_webview] Use a fraction to calculate scroll offset.

android_webview/browser/browser_view_renderer.h

Index: android_webview/browser/browser_view_renderer.h
diff --git a/android_webview/browser/browser_view_renderer.h b/android_webview/browser/browser_view_renderer.h
index f54420c6422e1fe4f4c31be6a5a864125e779ce4..0ae9538484cbafb764625d40288befcba32dc1ca 100644
--- a/android_webview/browser/browser_view_renderer.h
+++ b/android_webview/browser/browser_view_renderer.h
@@ -48,6 +48,15 @@ class BrowserViewRenderer {
     // Try to set the view's scroll offset to |new_value|.
     virtual void ScrollContainerViewTo(gfx::Vector2d new_value) = 0;
 
+    // Set the view's scroll offset cap to |new_value|.
+    virtual void SetMaxContainerViewScrollOffset(gfx::Vector2d new_value) = 0;
+
+    // Set the current page scale to |page_scale_factor|.
+    virtual void SetPageScaleFactor(float page_scale_factor) = 0;
+
+    // Set the current contents_size to |contents_size_dip|.
+    virtual void SetContentsSize(gfx::SizeF contents_size_dip) = 0;
+
     // Handle overscroll.
     virtual void DidOverscroll(gfx::Vector2d overscroll_delta) = 0;
 
@@ -122,7 +131,6 @@ class BrowserViewRenderer {
 
   // Sets the scale for logical<->physical pixel conversions.
   virtual void SetDipScale(float dip_scale) = 0;
-  virtual void SetPageScaleFactor(float page_scale_factor) = 0;
 
   // Set the root layer scroll offset to |new_value|.
   virtual void ScrollTo(gfx::Vector2d new_value) = 0;