Add ExternalPrerenderRequestHandler and related API

chrome/browser/prerender/external_prerender_handler_android.cc

+// 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.
+
+#include "chrome/browser/prerender/external_prerender_handler_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/prerender/prerender_handle.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/prerender/prerender_manager_factory.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_android.h"
+#include "content/public/browser/web_contents.h"
+
+#include "jni/ExternalPrerenderHandler_jni.h"
+
+using base::android::ConvertJavaStringToUTF16;
+
+namespace prerender {
+
+bool ExternalPrerenderHandlerAndroid::AddPrerender(JNIEnv* env,
+                                                  jobject obj,

[cbentzel, 2013/11/01 10:45:20]

Nit: indent by one line.

[Yusuf, 2013/11/01 17:04:01]

Done.

+                                                  jobject jprofile,
+                                                  jint web_contents_ptr,
+                                                  jstring jurl,
+                                                  jstring jreferrer,
+                                                  jint width,
+                                                  jint height) {
+  Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
+
+  GURL url = GURL(ConvertJavaStringToUTF16(env, jurl));
+  if (!url.is_valid())
+    return 0;

[cbentzel, 2013/11/01 10:45:20]

Nit: return false;

[Yusuf, 2013/11/01 17:04:01]

Done.

+
+  GURL referrer_url = GURL(ConvertJavaStringToUTF16(env, jreferrer));
+  content::Referrer referrer = referrer_url.is_valid() ?
+      content::Referrer(referrer_url, WebKit::WebReferrerPolicyDefault) :
+      content::Referrer();
+
+  PrerenderManager* prerender_manager =
+      prerender::PrerenderManagerFactory::GetForProfile(profile);
+  if (!prerender_manager)
+    return false;
+  content::WebContents* web_contents =
+      reinterpret_cast<content::WebContents*>(web_contents_ptr);

[cbentzel, 2013/11/01 10:45:20]

Is this the only way to do the casting - really wish there was a safer way, but
I don't know enough about the Java/JNI bindings used.

[Yusuf, 2013/11/01 17:04:01]

AFAIK, this the way to have Java classes hold on to pointers to native
instances. In classes where Java side manages the life cycle we have a lot of
int mNativeClassNameHere.

On 2013/11/01 10:45:20, cbentzel wrote:

+  if (prerender_handle_.get()) {
+    prerender_handle_->OnNavigateAway();
+    // The PrerenderHandle is now owned by the PrerenderManager.
+    ignore_result(prerender_handle_.release());
+  }
+  prerender_handle_.reset(

[cbentzel, 2013/11/01 10:45:20]

t's possible that this won't be able to create a prerender - would you still
want to cancel the old prerender in that case?

[Yusuf, 2013/11/01 17:04:01]

Yes. I think I would want cancelCurrentPrerender to function like relieving the
prerenderHandler instance from its current task.


On 2013/11/01 10:45:20, cbentzel wrote:

+      prerender_manager->AddPrerenderFromExternalRequest(
+          url,
+          referrer,
+          web_contents->GetController().GetDefaultSessionStorageNamespace(),
+          gfx::Size(width, height)));
+  if (!prerender_handle_)
+    return false;
+  return true;
+}
+
+void ExternalPrerenderHandlerAndroid::CancelCurrentPrerender(JNIEnv* env,
+                                                             jobject object) {
+  if(prerender_handle_)

[cbentzel, 2013/11/01 10:45:20]

Nit: space between if and (

[Yusuf, 2013/11/01 17:04:01]

Done.

+    prerender_handle_->OnCancel();
+}
+
+static jboolean HasPrerenderedUrl(JNIEnv* env,
+                                  jclass clazz,
+                                  jobject jprofile,
+                                  jstring jurl,
+                                  jint web_contents_ptr) {
+    Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);

[cbentzel, 2013/11/01 10:45:20]

Nit: these all look incorrectly indented - should only be by 2.

[Yusuf, 2013/11/01 17:04:01]

Done.

+    GURL url;
+    if (jurl != NULL)

[cbentzel, 2013/11/01 10:45:20]

Does it make sense for jurl to be NULL? Should we just early return in that
case?

[Yusuf, 2013/11/01 17:04:01]

Done.

+      url = GURL(ConvertJavaStringToUTF16(env, jurl));
+    if (!url.is_valid())
+      return false;
+    prerender::PrerenderManager* prerender_manager =
+            prerender::PrerenderManagerFactory::GetForProfile(profile);
+    if (!prerender_manager)
+      return false;
+    content::WebContents* web_contents =
+        reinterpret_cast<content::WebContents*>(web_contents_ptr);
+    return prerender_manager->HasPrerenderedUrl(url, web_contents);
+}
+
+ExternalPrerenderHandlerAndroid::ExternalPrerenderHandlerAndroid() {}
+
+ExternalPrerenderHandlerAndroid::~ExternalPrerenderHandlerAndroid() {}
+
+static jint Init(JNIEnv* env,
+                 jclass clazz) {
+  ExternalPrerenderHandlerAndroid* external_handler =
+      new ExternalPrerenderHandlerAndroid();
+  return reinterpret_cast<jint>(external_handler);
+}
+
+bool ExternalPrerenderHandlerAndroid::RegisterExternalPrerenderHandlerAndroid(
+    JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+} // namespace prerender