Add support for distilling current WebContents

chrome/android/java/src/org/chromium/chrome/browser/dom_distiller/DomDistillerTabUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/dom_distiller/DomDistillerTabUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/dom_distiller/DomDistillerTabUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/dom_distiller/DomDistillerTabUtils.java
new file mode 100644
index 0000000000000000000000000000000000000000..06b75628985073bf2c1ec3234fc0baa18339bf50
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/dom_distiller/DomDistillerTabUtils.java
@@ -0,0 +1,32 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.dom_distiller;
+
+import org.chromium.base.JNINamespace;
+import org.chromium.chrome.browser.Tab;
+import org.chromium.content_public.browser.WebContents;
+
+/**
+ * A helper class for using the DOM Distiller.
+ */
+@JNINamespace("dom_distiller::tab_utils::android")
+public class DomDistillerTabUtils {
+
+    private DomDistillerTabUtils() {
+    }
+
+    /**
+     * Creates a new WebContents and navigates the {@link Tab} to view the URL of the current page,
+     * while in the background starts distilling the current page. This method takes ownership
+     * over the old WebContents after swapping in the new one.
+     *
+     * @param tab the {@link Tab} to distill and navigate.
+     */
+    public static void distillCurrentPageAndView(Tab tab) {

[Yaron, 2014/05/06 00:23:20]

Just pass WebContents directly. Comment seems out of date too. Can this be done
inside the component since it only deps on WC? Maybe even re-use the current JNI
rebinding and re-purpose as "DomDistillerService" api?

[nyquist, 2014/05/06 03:52:27]

DomDistillerService should not depend on WebContents, since it's from //content.

Then for just putting it in //components/dom_distiller/content/: The
implementation of this in C++ needs to have access to
//chrome/browser/ui/tab_contents/core_tab_helper[|_delegate].[cc|h] and
chrome/browser/dom_distiller/dom_distiller_service_factory.h.

The latter we could remove by just passing in DomDistillerService from the
caller, but the CoreTabHelper stuff seems hard to fix.

[nyquist, 2014/05/15 10:15:35]

Changed to take WebContents here.

+        nativeDistillCurrentPageAndViewJava(tab.getContentViewCore().getWebContents());
+    }
+
+    private static native void nativeDistillCurrentPageAndViewJava(WebContents webContents);
+}