[Instant Start] Pass TabModelSelector in StaticLayout's constructor.

The crash is caused by mTabModelSelector is null when
StaticLayout#show() is called. However, the TabModelSelector should have
been created before StaticLayout is created in LayoutManager#Init().
This CL refactors the StaticLayout by passing the TabModelSelector
object to its constructor, rather than a TabModelSelectorSupplier.

Bug: 1123448
Change-Id: I5184b23316690313fc27684d71f0766df47b007c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2385980
Commit-Queue: Xi Han <hanxi@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803685}

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java

@@ -160,8 +160,6 @@ public class LayoutManager implements LayoutUpdateHost, LayoutProvider,
      */
     private ObservableSupplierImpl<Tab> mCurrentTabSupplier;
 
-    private final ObservableSupplierImpl<TabModelSelector> mTabModelSelectorSupplier =
-            new ObservableSupplierImpl<>();
     private final ObservableSupplierImpl<TabContentManager> mTabContentManagerSupplier =
             new ObservableSupplierImpl<>();
     private final ObservableSupplierImpl<BrowserControlsStateProvider>
@@ -418,8 +416,7 @@ public class LayoutManager implements LayoutUpdateHost, LayoutProvider,
 
         // Build Layouts
         mStaticLayout = new StaticLayout(mContext, this, renderHost, mHost, mFrameRequestSupplier,
-                mTabModelSelectorSupplier, mTabContentManagerSupplier,
-                mBrowserControlsStateProviderSupplier);
+                selector, mTabContentManagerSupplier, mBrowserControlsStateProviderSupplier);
 
         // Set up layout parameters
         mStaticLayout.setLayoutHandlesTabLifecycles(true);
@@ -472,9 +469,10 @@ public class LayoutManager implements LayoutUpdateHost, LayoutProvider,
         }
     }
 
+    // TODO(hanxi): Passes the TabModelSelectorSupplier in the constructor since the
+    // mTabModelSelector should only be set once.
     public void setTabModelSelector(TabModelSelector selector) {
         mTabModelSelector = selector;
-        mTabModelSelectorSupplier.set(selector);
         mCurrentTabSupplier.set(selector.getCurrentTab());
         mTabModelSelectorTabObserver = new TabModelSelectorTabObserver(mTabModelSelector) {
             @Override

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java

@@ -110,7 +110,7 @@ public class StaticLayout extends Layout {
     public StaticLayout(Context context, LayoutUpdateHost updateHost, LayoutRenderHost renderHost,
             LayoutManagerHost viewHost,
             CompositorModelChangeProcessor.FrameRequestSupplier requestSupplier,
-            ObservableSupplier<TabModelSelector> tabModelSelectoSupplier,
+            TabModelSelector tabModelSelector,
             ObservableSupplier<TabContentManager> tabContentManagerSupplier,
             ObservableSupplier<BrowserControlsStateProvider> browserControlsStateProviderSupplier) {
         super(context, updateHost, renderHost);
@@ -118,13 +118,8 @@ public class StaticLayout extends Layout {
         mViewHost = viewHost;
         mRequestSupplier = requestSupplier;
 
-        tabModelSelectoSupplier.addObserver(new Callback<TabModelSelector>() {
-            @Override
-            public void onResult(TabModelSelector tabModelSelector) {
-                setTabModelSelector(tabModelSelector);
-                tabModelSelectoSupplier.removeObserver(this);
-            }
-        });
+        assert tabModelSelector != null;
+        setTabModelSelector(tabModelSelector);
 
         tabContentManagerSupplier.addObserver(new Callback<TabContentManager>() {
             @Override

chrome/android/junit/src/org/chromium/chrome/browser/compositor/layouts/StaticLayoutUnitTest.java

@@ -117,8 +117,6 @@ public class StaticLayoutUnitTest {
     private ArgumentCaptor<TabObserver> mTabObserverCaptor;
 
     private CompositorAnimationHandler mCompositorAnimationHandler;
-    private ObservableSupplierImpl<TabModelSelector> mTabModelSelectoSupplier =
-            new ObservableSupplierImpl<>();
     private ObservableSupplierImpl<TabContentManager> mTabContentManagerSupplier =
             new ObservableSupplierImpl<>();
     private ObservableSupplierImpl<BrowserControlsStateProvider>
@@ -165,7 +163,7 @@ public class StaticLayoutUnitTest {
         doReturn(mCompositorAnimationHandler).when(mUpdateHost).getAnimationHandler();
 
         mStaticLayout = new StaticLayout(mContext, mUpdateHost, mRenderHost, mViewHost,
-                mRequestSupplier, mTabModelSelectoSupplier, mTabContentManagerSupplier,
+                mRequestSupplier, mTabModelSelector, mTabContentManagerSupplier,
                 mBrowserControlsStateProviderSupplier);
         mModel = mStaticLayout.getModelForTesting();
 
@@ -195,10 +193,6 @@ public class StaticLayoutUnitTest {
     }
 
     private void initAndAssertAllDependencies() {
-        assertNull(mStaticLayout.getTabModelSelectorForTesting());
-        mTabModelSelectoSupplier.set(mTabModelSelector);
-        assertEquals(mTabModelSelector, mStaticLayout.getTabModelSelectorForTesting());
-
         assertNull(mStaticLayout.getTabContentManagerForTesting());
         mTabContentManagerSupplier.set(mTabContentManager);
         assertEquals(mTabContentManager, mStaticLayout.getTabContentManagerForTesting());