Add theme color for Blimp on Android.

Use Material Design color Light Blue 100 for a Blimp tab.
See https://material.google.com/style/color.html for details.

BUG=64425

Review-Url: https://codereview.chromium.org/2315953002
Cr-Commit-Position: refs/heads/master@{#417079}

blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsImpl.java

@@ -25,6 +25,9 @@ public class BlimpContentsImpl implements BlimpContents {
                 nativeBlimpContentsImplAndroid, navigationController, blimpView);
     }
 
+    // Light blue theme color on Blimp tab.
+    private static final int BLIMP_THEME_COLOR = 0xb3e5fc;
+
     private long mNativeBlimpContentsImplAndroid;
 
     // Given the importance of the navigation controller, this member is kept directly in Java to
@@ -72,6 +75,13 @@ public class BlimpContentsImpl implements BlimpContents {
         return mBlimpNavigationController;
     }
 
+    // TODO(xingliu): Use the correct theme color for Blimp.
+    // crbug.com/644774
+    @Override
+    public int getThemeColor() {
+        return BLIMP_THEME_COLOR;
+    }
+
     @Override
     public void addObserver(BlimpContentsObserver observer) {
         assert mNativeBlimpContentsImplAndroid != 0;

blimp/client/public/android/java/src/org/chromium/blimp_public/contents/BlimpContents.java

@@ -20,6 +20,11 @@ public interface BlimpContents {
      */
     BlimpNavigationController getNavigationController();
 
+    /**
+     * Returns the theme color for Blimp tab.
+     */
+    int getThemeColor();
+
     /**
      * Adds an observer to this BlimpContents.
      */

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

@@ -1114,6 +1114,12 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
             if (themeColor != 0 && !ColorUtils.isValidThemeColor(themeColor)) themeColor = 0;
         }
 
+        // Apply theme color for Blimp tab.
+        if (isBlimpTab() && getBlimpContents() != null) {
+            themeColor = getBlimpContents().getThemeColor();
+            if (themeColor != 0 && !ColorUtils.isValidThemeColor(themeColor)) themeColor = 0;
+        }
+
         // Do not apply the theme color if there are any security issues on the page.
         int securityLevel = getSecurityLevel();
         if (securityLevel == ConnectionSecurityLevel.SECURITY_ERROR