Add ExternalPrerenderRequestHandler and related API

chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java
new file mode 100644
index 0000000000000000000000000000000000000000..4d0da7f4e09f502cc6e4de2344fc77bef70be9a4
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/prerender/ExternalPrerenderHandler.java
@@ -0,0 +1,50 @@
+// Copyright (c) 2013 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.prerender;
+
+import org.chromium.base.JNINamespace;
+import org.chromium.chrome.browser.ContentViewUtil;
+import org.chromium.chrome.browser.profiles.Profile;
+
+/**
+ * A handler class for prerender requests coming from  other applications.
+ */
+@JNINamespace("prerender")
+public class ExternalPrerenderHandler {
+
+    private int mNativeExternalPrerenderHandler;
+
+    public ExternalPrerenderHandler() {
+        mNativeExternalPrerenderHandler = nativeInit();
+    }
+
+    public int addPrerender(Profile profile, String url, String referrer, int width, int height) {
+        if (mNativeExternalPrerenderHandler == 0) return 0;
+        int webContentsPtr = ContentViewUtil.createNativeWebContents(false);
+        if (nativeAddPrerender(mNativeExternalPrerenderHandler, profile, webContentsPtr,
+                url, referrer, width, height)) {
+            return webContentsPtr;
+        }
+        return 0;
+    }
+
+    public void cancelCurrentPrerender() {
+        if (mNativeExternalPrerenderHandler == 0) return;
+        nativeCancelCurrentPrerender(mNativeExternalPrerenderHandler);
+    }
+
+    public static boolean hasPrerenderedUrl(Profile profile, String url, int webContentsPtr)  {
+        return nativeHasPrerenderedUrl(profile, url, webContentsPtr);
+    }
+
+    private static native int nativeInit();
+    private static native boolean nativeAddPrerender(
+            int nativeExternalPrerenderHandlerAndroid, Profile profile,
+            int webContentsPtr, String url, String referrer, int width, int height);
+    private static native boolean nativeHasPrerenderedUrl(
+            Profile profile, String url, int webContentsPtr);
+    private static native void nativeCancelCurrentPrerender(
+            int nativeExternalPrerenderHandlerAndroid);
+}