CompositorViewHolder is source of truth for viewports

chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java b/chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java
index e0dcda7c0fe2148ca6c9d157f2fb124519048e9f..26710920e372e41683cd7e648028b5c3943c0e29 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/compositor/layouts/MockLayoutHost.java
@@ -6,6 +6,7 @@ package org.chromium.chrome.browser.compositor.layouts;
 
 import android.content.Context;
 import android.graphics.Rect;
+import android.graphics.RectF;
 
 import org.chromium.chrome.browser.compositor.TitleCache;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
@@ -83,6 +84,21 @@ class MockLayoutHost implements LayoutManagerHost, LayoutRenderHost {
     }
 
     @Override
+    public void getWindowViewport(RectF outRect) {
+        outRect.set(0, 0, getWidth(), getHeight());
+    }
+
+    @Override
+    public void getVisibleViewport(RectF outRect) {
+        outRect.set(0, 0, getWidth(), getHeight());
+    }
+
+    @Override
+    public float getHeightMinusBrowserControls() {
+        return getHeight();
+    }
+
+    @Override
     public LayoutRenderHost getLayoutRenderHost() {
         return this;
     }