[Android] Allow custom ActionMode creation via ContentViewClient

android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java

Index: android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java b/android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java
index 2246be3001505b040513befab9e83a2967bc78a5..7b1add10d51d09369623f270ffd01111bb450275 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContentViewClient.java
@@ -19,6 +19,8 @@ import android.widget.FrameLayout;
 import org.chromium.content.browser.ContentVideoViewClient;
 import org.chromium.content.browser.ContentViewClient;
 import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content.browser.SelectActionMode;
+import org.chromium.content.browser.SelectActionModeCallback.ActionHandler;
 
 import java.net.URISyntaxException;
 
@@ -105,6 +107,19 @@ public class AwContentViewClient extends ContentViewClient implements ContentVid
     }
 
     @Override
+    public SelectActionMode startActionMode(
+            View view, ActionHandler actionHandler, boolean floating) {
+        SelectActionMode mode = mAwContentsClient.startActionMode(view, actionHandler, floating);
+        if (mode != null) return mode;
+        return super.startActionMode(view, actionHandler, floating);
+    }
+
+    @Override
+    public boolean supportsFloatingActionMode() {
+        return mAwContentsClient.supportsFloatingActionMode();
+    }
+
+    @Override
     public final ContentVideoViewClient getContentVideoViewClient() {
         return this;
     }