[android_webview] Use a fraction to calculate scroll offset.

content/browser/android/in_process/synchronous_compositor_impl.cc

Index: content/browser/android/in_process/synchronous_compositor_impl.cc
diff --git a/content/browser/android/in_process/synchronous_compositor_impl.cc b/content/browser/android/in_process/synchronous_compositor_impl.cc
index b04e85456f1d7f0095f97c66bc9f821f3f035731..191891aa5e922999d2d1f2b3f7cca3b77e1e5349 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.cc
+++ b/content/browser/android/in_process/synchronous_compositor_impl.cc
@@ -415,10 +415,18 @@ void SynchronousCompositorImpl::DidActivatePendingTree() {
     compositor_client_->DidUpdateContent();
 }
 
-void SynchronousCompositorImpl::SetTotalScrollOffset(gfx::Vector2dF new_value) {
+void SynchronousCompositorImpl::SetMaxScrollOffset(
+    gfx::Vector2dF max_scroll_offset) {
   DCHECK(CalledOnValidThread());
   if (compositor_client_)
+    compositor_client_->SetMaxRootLayerScrollOffset(max_scroll_offset);
+}
+
+void SynchronousCompositorImpl::SetTotalScrollOffset(gfx::Vector2dF new_value) {
+  DCHECK(CalledOnValidThread());
+  if (compositor_client_) {
     compositor_client_->SetTotalRootLayerScrollOffset(new_value);
+  }
 }
 
 gfx::Vector2dF SynchronousCompositorImpl::GetTotalScrollOffset() {