Fix blank page after changing theme

Getting the value of a null IntPropertyKey from a PropertyModel returns
0. This behavior causes the StaticLayout not setting the tab correctly
when the tab id is 0, which leads to the blank page issue. This CL fixes
this issue by initializing the TAB_ID IntPropertyKey to
Tab.INVALID_TAB_ID.

Bug: 1108693
Change-Id: I929b16327c2b7f57e7acd698ed235eadfdc0bbe2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2327187Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Mei Liang <meiliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792864}

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

@@ -145,6 +145,7 @@ public class StaticLayout extends Layout {
                 });
 
         mModel = new PropertyModel.Builder(LayoutTab.ALL_KEYS)
+                         .with(LayoutTab.TAB_ID, Tab.INVALID_TAB_ID)
                          .with(LayoutTab.SCALE, 1.0f)
                          .with(LayoutTab.X, 0.0f)
                          .with(LayoutTab.Y, 0.0f)

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

@@ -60,7 +60,7 @@ import java.util.LinkedList;
 @RunWith(BaseRobolectricTestRunner.class)
 @Config(manifest = Config.NONE)
 public class StaticLayoutUnitTest {
-    private static final int TAB1_ID = 456;
+    private static final int TAB1_ID = 0;
     private static final int TAB2_ID = 789;
     private static final int POSITION1 = 0;
     private static final int POSITION2 = 1;
@@ -181,6 +181,7 @@ public class StaticLayoutUnitTest {
         initAndAssertAllDependencies();
 
         mStaticLayout.show(System.currentTimeMillis(), false);
+        initAndAssertAllProperties();
     }
 
     @After
@@ -208,6 +209,23 @@ public class StaticLayoutUnitTest {
                 mStaticLayout.getBrowserControlsStateProviderForTesting());
     }
 
+    private void initAndAssertAllProperties() {
+        assertEquals(mTab1, mTabModelSelector.getCurrentTab());
+        assertEquals(TAB1_ID, mModel.get(LayoutTab.TAB_ID));
+        assertEquals(WIDTH, mModel.get(LayoutTab.ORIGINAL_CONTENT_WIDTH_IN_DP), 0);
+        assertEquals(HEIGHT, mModel.get(LayoutTab.ORIGINAL_CONTENT_HEIGHT_IN_DP), 0);
+        assertEquals(WIDTH, mModel.get(LayoutTab.MAX_CONTENT_WIDTH), 0);
+        assertEquals(HEIGHT, mModel.get(LayoutTab.MAX_CONTENT_HEIGHT), 0);
+        assertEquals(BACKGROUND_COLOR, mModel.get(LayoutTab.BACKGROUND_COLOR));
+        assertEquals(TOOLBAR_BACKGROUND_COLOR, mModel.get(LayoutTab.TOOLBAR_BACKGROUND_COLOR));
+        assertEquals(TEXT_BOX_ALPHA, mModel.get(LayoutTab.TEXT_BOX_ALPHA), 0);
+        assertEquals(TEXT_BOX_BACKGROUND_COLOR, mModel.get(LayoutTab.TEXT_BOX_BACKGROUND_COLOR));
+
+        assertFalse(mModel.get(LayoutTab.IS_INCOGNITO));
+        assertFalse(mModel.get(LayoutTab.SHOULD_STALL));
+        assertTrue(mModel.get(LayoutTab.CAN_USE_LIVE_TEXTURE));
+    }
+
     private Tab prepareTab(int id, String url) {
         Tab tab = mock(Tab.class);
         doReturn(id).when(tab).getId();