Introduce bottom controls to CC and let it respond to scrolling

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
index b168c932c13076965547540bdaf3e825c40061ae..9b68a492cb71c366123be0d7bb2034b965c70047 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
@@ -350,7 +350,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     private TabRedirectHandler mTabRedirectHandler;
 
     private FullscreenManager mFullscreenManager;
-    private float mPreviousFullscreenTopControlsOffsetY = Float.NaN;
+    private float mPreviousTopControlsTranslate = Float.NaN;
     private float mPreviousFullscreenContentOffsetY = Float.NaN;
     private int mFullscreenHungRendererToken = FullscreenManager.INVALID_TOKEN;
     private boolean mIsFullscreenWaitingForLoad = false;
@@ -391,9 +391,8 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
         }
 
         @Override
-        public void onOffsetsForFullscreenChanged(
-                float topControlsOffsetY, float contentOffsetY) {
-            onOffsetsChanged(topControlsOffsetY, contentOffsetY, isShowingSadTab());
+        public void onTopControlsChanged(float topControlsOffsetY, float topControlsShownY) {

[bokan, 2016/07/01 17:19:14]

Did we drop `Fullscreen` in the name intentionally here?

[Ian Wen, 2016/07/06 20:53:44]

Yes. The term "fullscreen" is, IMO, out dated and overloaded. It was first
introduced for the project to hide the top controls, later video/html5
fullscreen also utilized part of the code. What I am trying to do here is to
slowly remove the term "fullscreen" from the top controls code.

+            onOffsetsChanged(topControlsOffsetY, topControlsShownY, isShowingSadTab());
         }
 
         @Override
@@ -2038,7 +2037,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
             mAppBannerManager = null;
         }
 
-        mPreviousFullscreenTopControlsOffsetY = Float.NaN;
+        mPreviousTopControlsTranslate = Float.NaN;
         mPreviousFullscreenContentOffsetY = Float.NaN;
 
         mNeedsReload = false;
@@ -2671,20 +2670,20 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     /**
      * Called when offset values related with fullscreen functionality has been changed by the
      * compositor.
-     * @param topControlsOffsetY The Y offset of the top controls in physical pixels.
-     * @param contentOffsetY The Y offset of the content in physical pixels.
+     * @param topControlsTranslate The Y offset of the top controls in physical pixels.
+     * @param topControlsShown The Y offset of the content in physical pixels.
      * @param isNonFullscreenPage Whether a current page is non-fullscreen page or not.
      */
-    private void onOffsetsChanged(float topControlsOffsetY, float contentOffsetY,
+    private void onOffsetsChanged(float topControlsTranslate, float topControlsShown,
             boolean isNonFullscreenPage) {
-        mPreviousFullscreenTopControlsOffsetY = topControlsOffsetY;
-        mPreviousFullscreenContentOffsetY = contentOffsetY;
+        mPreviousTopControlsTranslate = topControlsTranslate;
+        mPreviousFullscreenContentOffsetY = topControlsShown;
 
         if (mFullscreenManager == null) return;
         if (isNonFullscreenPage || isNativePage()) {
             mFullscreenManager.setPositionsForTabToNonFullscreen();
         } else {
-            mFullscreenManager.setPositionsForTab(topControlsOffsetY, contentOffsetY);
+            mFullscreenManager.setPositionsForTab(topControlsTranslate, topControlsShown);
         }
         TabModelImpl.setActualTabSwitchLatencyMetricRequired();
     }
@@ -2812,12 +2811,12 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     public void setFullscreenManager(FullscreenManager manager) {
         mFullscreenManager = manager;
         if (mFullscreenManager != null) {
-            if (Float.isNaN(mPreviousFullscreenTopControlsOffsetY)
+            if (Float.isNaN(mPreviousTopControlsTranslate)
                     || Float.isNaN(mPreviousFullscreenContentOffsetY)) {
                 mFullscreenManager.setPositionsForTabToNonFullscreen();
             } else {
                 mFullscreenManager.setPositionsForTab(
-                        mPreviousFullscreenTopControlsOffsetY, mPreviousFullscreenContentOffsetY);
+                        mPreviousTopControlsTranslate, mPreviousFullscreenContentOffsetY);
             }
             mFullscreenManager.showControlsTransient();
             updateFullscreenEnabledState();