Pass method parameters as JavaParamRef in android_webview.

Pass all object parameters to JNI methods in JavaParamRef<> wrappers.
This matches previous changes made to do this for JNI non-method
functions.

BUG=506850

Review URL: https://codereview.chromium.org/1492703004

Cr-Commit-Position: refs/heads/master@{#363198}

21 files changed, 454 insertions, 241 deletions

diff --git a/android_webview/native/aw_autofill_client.cc b/android_webview/native/aw_autofill_client.cc
index 2b2c2667..911571a 100644
--- a/android_webview/native/aw_autofill_client.cc
+++ b/android_webview/native/aw_autofill_client.cc
@@ -194,7 +194,7 @@ bool AwAutofillClient::IsContextSecure(const GURL& form_origin) {
 }
 
 void AwAutofillClient::SuggestionSelected(JNIEnv* env,
-                                          jobject object,
+                                          const JavaParamRef<jobject>& object,
                                           jint position) {
   if (delegate_) {
     delegate_->DidAcceptSuggestion(suggestions_[position].value,
diff --git a/android_webview/native/aw_autofill_client.h b/android_webview/native/aw_autofill_client.h
index c869ddb..b4278ed 100644
--- a/android_webview/native/aw_autofill_client.h
+++ b/android_webview/native/aw_autofill_client.h
@@ -96,7 +96,9 @@ class AwAutofillClient : public autofill::AutofillClient,
   void OnFirstUserGestureObserved() override;
   bool IsContextSecure(const GURL& form_origin) override;
 
-  void SuggestionSelected(JNIEnv* env, jobject obj, jint position);
+  void SuggestionSelected(JNIEnv* env,
+                          const base::android::JavaParamRef<jobject>& obj,
+                          jint position);
 
  private:
   AwAutofillClient(content::WebContents* web_contents);
diff --git a/android_webview/native/aw_contents.cc b/android_webview/native/aw_contents.cc
index 8ec6260..a3bcf2f 100644
--- a/android_webview/native/aw_contents.cc
+++ b/android_webview/native/aw_contents.cc
@@ -213,13 +213,14 @@ AwContents::AwContents(scoped_ptr<WebContents> web_contents)
   AwContentsLifecycleNotifier::OnWebViewCreated();
 }
 
-void AwContents::SetJavaPeers(JNIEnv* env,
-                              jobject obj,
-                              jobject aw_contents,
-                              jobject web_contents_delegate,
-                              jobject contents_client_bridge,
-                              jobject io_thread_client,
-                              jobject intercept_navigation_delegate) {
+void AwContents::SetJavaPeers(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jobject>& aw_contents,
+    const JavaParamRef<jobject>& web_contents_delegate,
+    const JavaParamRef<jobject>& contents_client_bridge,
+    const JavaParamRef<jobject>& io_thread_client,
+    const JavaParamRef<jobject>& intercept_navigation_delegate) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   // The |aw_content| param is technically spurious as it duplicates |obj| but
   // is passed over anyway to make the binding more explicit.
@@ -234,8 +235,8 @@ void AwContents::SetJavaPeers(JNIEnv* env,
   AwContentsClientBridgeBase::Associate(web_contents_.get(),
                                         contents_client_bridge_.get());
 
-  AwContentsIoThreadClientImpl::Associate(
-      web_contents_.get(), ScopedJavaLocalRef<jobject>(env, io_thread_client));
+  AwContentsIoThreadClientImpl::Associate(web_contents_.get(),
+                                          io_thread_client);
 
   InterceptNavigationDelegate::Associate(
       web_contents_.get(),
@@ -303,8 +304,9 @@ AwContents::~AwContents() {
   AwContentsLifecycleNotifier::OnWebViewDestroyed();
 }
 
-base::android::ScopedJavaLocalRef<jobject>
-AwContents::GetWebContents(JNIEnv* env, jobject obj) {
+base::android::ScopedJavaLocalRef<jobject> AwContents::GetWebContents(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(web_contents_);
   if (!web_contents_)
@@ -313,7 +315,7 @@ AwContents::GetWebContents(JNIEnv* env, jobject obj) {
   return web_contents_->GetJavaWebContents();
 }
 
-void AwContents::Destroy(JNIEnv* env, jobject obj) {
+void AwContents::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   java_ref_.reset();
   delete this;
 }
@@ -357,7 +359,8 @@ jint GetNativeInstanceCount(JNIEnv* env, const JavaParamRef<jclass>&) {
   return base::subtle::NoBarrier_Load(&g_instance_count);
 }
 
-jlong AwContents::GetAwDrawGLViewContext(JNIEnv* env, jobject obj) {
+jlong AwContents::GetAwDrawGLViewContext(JNIEnv* env,
+                                         const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return reinterpret_cast<intptr_t>(
       browser_view_renderer_.GetAwDrawGLViewContext());
@@ -372,7 +375,9 @@ void DocumentHasImagesCallback(const ScopedJavaGlobalRef<jobject>& message,
 }
 }  // namespace
 
-void AwContents::DocumentHasImages(JNIEnv* env, jobject obj, jobject message) {
+void AwContents::DocumentHasImages(JNIEnv* env,
+                                   const JavaParamRef<jobject>& obj,
+                                   const JavaParamRef<jobject>& message) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ScopedJavaGlobalRef<jobject> j_message;
   j_message.Reset(env, message);
@@ -392,8 +397,10 @@ void GenerateMHTMLCallback(ScopedJavaGlobalRef<jobject>* callback,
 }
 }  // namespace
 
-void AwContents::GenerateMHTML(JNIEnv* env, jobject obj,
-                               jstring jpath, jobject callback) {
+void AwContents::GenerateMHTML(JNIEnv* env,
+                               const JavaParamRef<jobject>& obj,
+                               const JavaParamRef<jstring>& jpath,
+                               const JavaParamRef<jobject>& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ScopedJavaGlobalRef<jobject>* j_callback = new ScopedJavaGlobalRef<jobject>();
   j_callback->Reset(env, callback);
@@ -404,8 +411,8 @@ void AwContents::GenerateMHTML(JNIEnv* env, jobject obj,
 }
 
 void AwContents::CreatePdfExporter(JNIEnv* env,
-                                   jobject obj,
-                                   jobject pdfExporter) {
+                                   const JavaParamRef<jobject>& obj,
+                                   const JavaParamRef<jobject>& pdfExporter) {
   pdf_exporter_.reset(
       new AwPdfExporter(env,
                         pdfExporter,
@@ -435,9 +442,10 @@ void AwContents::SetOffscreenPreRaster(bool enabled) {
   browser_view_renderer_.SetOffscreenPreRaster(enabled);
 }
 
-void AwContents::AddVisitedLinks(JNIEnv* env,
-                                   jobject obj,
-                                   jobjectArray jvisited_links) {
+void AwContents::AddVisitedLinks(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jobjectArray>& jvisited_links) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   std::vector<base::string16> visited_link_strings;
   base::android::AppendJavaStringArrayToStringVector(
@@ -503,10 +511,11 @@ void AwContents::ShowGeolocationPrompt(const GURL& requesting_frame,
 }
 
 // Invoked from Java
-void AwContents::InvokeGeolocationCallback(JNIEnv* env,
-                                           jobject obj,
-                                           jboolean value,
-                                           jstring origin) {
+void AwContents::InvokeGeolocationCallback(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    jboolean value,
+    const JavaParamRef<jstring>& origin) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (pending_geolocation_prompts_.empty())
     return;
@@ -581,11 +590,10 @@ void AwContents::OnPermissionRequestCanceled(AwPermissionRequest* request) {
       env, j_ref.obj(), j_request.obj());
 }
 
-void AwContents::PreauthorizePermission(
-    JNIEnv* env,
-    jobject obj,
-    jstring origin,
-    jlong resources) {
+void AwContents::PreauthorizePermission(JNIEnv* env,
+                                        const JavaParamRef<jobject>& obj,
+                                        const JavaParamRef<jstring>& origin,
+                                        jlong resources) {
   permission_request_handler_->PreauthorizePermission(
       GURL(base::android::ConvertJavaStringToUTF8(env, origin)), resources);
 }
@@ -648,25 +656,28 @@ void AwContents::CancelMIDISysexPermissionRequests(const GURL& origin) {
       origin, AwPermissionRequest::AwPermissionRequest::MIDISysex);
 }
 
-void AwContents::FindAllAsync(JNIEnv* env, jobject obj, jstring search_string) {
+void AwContents::FindAllAsync(JNIEnv* env,
+                              const JavaParamRef<jobject>& obj,
+                              const JavaParamRef<jstring>& search_string) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   GetFindHelper()->FindAllAsync(ConvertJavaStringToUTF16(env, search_string));
 }
 
-void AwContents::FindNext(JNIEnv* env, jobject obj, jboolean forward) {
+void AwContents::FindNext(JNIEnv* env,
+                          const JavaParamRef<jobject>& obj,
+                          jboolean forward) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   GetFindHelper()->FindNext(forward);
 }
 
-void AwContents::ClearMatches(JNIEnv* env, jobject obj) {
+void AwContents::ClearMatches(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   GetFindHelper()->ClearMatches();
 }
 
-void AwContents::ClearCache(
-    JNIEnv* env,
-    jobject obj,
-    jboolean include_disk_files) {
+void AwContents::ClearCache(JNIEnv* env,
+                            const JavaParamRef<jobject>& obj,
+                            jboolean include_disk_files) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   render_view_host_ext_->ClearCache();
 
@@ -764,7 +775,7 @@ void AwContents::OnNewPicture() {
 
 base::android::ScopedJavaLocalRef<jbyteArray> AwContents::GetCertificate(
     JNIEnv* env,
-    jobject obj) {
+    const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   content::NavigationEntry* entry =
       web_contents_->GetController().GetLastCommittedEntry();
@@ -785,7 +796,7 @@ base::android::ScopedJavaLocalRef<jbyteArray> AwContents::GetCertificate(
 }
 
 void AwContents::RequestNewHitTestDataAt(JNIEnv* env,
-                                         jobject obj,
+                                         const JavaParamRef<jobject>& obj,
                                          jfloat x,
                                          jfloat y,
                                          jfloat touch_major) {
@@ -795,7 +806,8 @@ void AwContents::RequestNewHitTestDataAt(JNIEnv* env,
   render_view_host_ext_->RequestNewHitTestDataAt(touch_center, touch_area);
 }
 
-void AwContents::UpdateLastHitTestData(JNIEnv* env, jobject obj) {
+void AwContents::UpdateLastHitTestData(JNIEnv* env,
+                                       const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!render_view_host_ext_->HasNewHitTestData()) return;
 
@@ -829,23 +841,33 @@ void AwContents::UpdateLastHitTestData(JNIEnv* env, jobject obj) {
                                     img_src.obj());
 }
 
-void AwContents::OnSizeChanged(JNIEnv* env, jobject obj,
-                               int w, int h, int ow, int oh) {
+void AwContents::OnSizeChanged(JNIEnv* env,
+                               const JavaParamRef<jobject>& obj,
+                               int w,
+                               int h,
+                               int ow,
+                               int oh) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.OnSizeChanged(w, h);
 }
 
-void AwContents::SetViewVisibility(JNIEnv* env, jobject obj, bool visible) {
+void AwContents::SetViewVisibility(JNIEnv* env,
+                                   const JavaParamRef<jobject>& obj,
+                                   bool visible) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.SetViewVisibility(visible);
 }
 
-void AwContents::SetWindowVisibility(JNIEnv* env, jobject obj, bool visible) {
+void AwContents::SetWindowVisibility(JNIEnv* env,
+                                     const JavaParamRef<jobject>& obj,
+                                     bool visible) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.SetWindowVisibility(visible);
 }
 
-void AwContents::SetIsPaused(JNIEnv* env, jobject obj, bool paused) {
+void AwContents::SetIsPaused(JNIEnv* env,
+                             const JavaParamRef<jobject>& obj,
+                             bool paused) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.SetIsPaused(paused);
   ContentViewCore* cvc =
@@ -855,17 +877,21 @@ void AwContents::SetIsPaused(JNIEnv* env, jobject obj, bool paused) {
   }
 }
 
-void AwContents::OnAttachedToWindow(JNIEnv* env, jobject obj, int w, int h) {
+void AwContents::OnAttachedToWindow(JNIEnv* env,
+                                    const JavaParamRef<jobject>& obj,
+                                    int w,
+                                    int h) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.OnAttachedToWindow(w, h);
 }
 
-void AwContents::OnDetachedFromWindow(JNIEnv* env, jobject obj) {
+void AwContents::OnDetachedFromWindow(JNIEnv* env,
+                                      const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.OnDetachedFromWindow();
 }
 
-bool AwContents::IsVisible(JNIEnv* env, jobject obj) {
+bool AwContents::IsVisible(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   return browser_view_renderer_.IsClientVisible();
 }
 
@@ -876,8 +902,9 @@ void AwContents::DetachFunctorFromView() {
     Java_AwContents_detachFunctorFromView(env, obj.obj());
 }
 
-base::android::ScopedJavaLocalRef<jbyteArray>
-AwContents::GetOpaqueState(JNIEnv* env, jobject obj) {
+base::android::ScopedJavaLocalRef<jbyteArray> AwContents::GetOpaqueState(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   // Required optimization in WebViewClassic to not save any state if
   // there has been no navigations.
@@ -894,7 +921,9 @@ AwContents::GetOpaqueState(JNIEnv* env, jobject obj) {
 }
 
 jboolean AwContents::RestoreFromOpaqueState(
-    JNIEnv* env, jobject obj, jbyteArray state) {
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jbyteArray>& state) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   // TODO(boliu): This copy can be optimized out if this is a performance
   // problem.
@@ -909,8 +938,8 @@ jboolean AwContents::RestoreFromOpaqueState(
 }
 
 bool AwContents::OnDraw(JNIEnv* env,
-                        jobject obj,
-                        jobject canvas,
+                        const JavaParamRef<jobject>& obj,
+                        const JavaParamRef<jobject>& canvas,
                         jboolean is_hardware_accelerated,
                         jint scroll_x,
                         jint scroll_y,
@@ -966,18 +995,20 @@ void AwContents::SetPendingWebContentsForPopup(
   pending_contents_->SetDipScaleInternal(browser_view_renderer_.dip_scale());
 }
 
-void AwContents::FocusFirstNode(JNIEnv* env, jobject obj) {
+void AwContents::FocusFirstNode(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   web_contents_->FocusThroughTabTraversal(false);
 }
 
-void AwContents::SetBackgroundColor(JNIEnv* env, jobject obj, jint color) {
+void AwContents::SetBackgroundColor(JNIEnv* env,
+                                    const JavaParamRef<jobject>& obj,
+                                    jint color) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   render_view_host_ext_->SetBackgroundColor(color);
 }
 
 void AwContents::OnComputeScroll(JNIEnv* env,
-                                 jobject obj,
+                                 const JavaParamRef<jobject>& obj,
                                  jlong animation_time_millis) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.OnComputeScroll(
@@ -985,7 +1016,8 @@ void AwContents::OnComputeScroll(JNIEnv* env,
       base::TimeDelta::FromMilliseconds(animation_time_millis));
 }
 
-jlong AwContents::ReleasePopupAwContents(JNIEnv* env, jobject obj) {
+jlong AwContents::ReleasePopupAwContents(JNIEnv* env,
+                                         const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return reinterpret_cast<intptr_t>(pending_contents_.release());
 }
@@ -1047,7 +1079,9 @@ void AwContents::DidOverscroll(const gfx::Vector2d& overscroll_delta,
                                 overscroll_velocity.y());
 }
 
-void AwContents::SetDipScale(JNIEnv* env, jobject obj, jfloat dip_scale) {
+void AwContents::SetDipScale(JNIEnv* env,
+                             const JavaParamRef<jobject>& obj,
+                             jfloat dip_scale) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   SetDipScaleInternal(dip_scale);
 }
@@ -1056,13 +1090,16 @@ void AwContents::SetDipScaleInternal(float dip_scale) {
   browser_view_renderer_.SetDipScale(dip_scale);
 }
 
-void AwContents::ScrollTo(JNIEnv* env, jobject obj, jint x, jint y) {
+void AwContents::ScrollTo(JNIEnv* env,
+                          const JavaParamRef<jobject>& obj,
+                          jint x,
+                          jint y) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.ScrollTo(gfx::Vector2d(x, y));
 }
 
 void AwContents::SmoothScroll(JNIEnv* env,
-                              jobject obj,
+                              const JavaParamRef<jobject>& obj,
                               jint target_x,
                               jint target_y,
                               jlong duration_ms) {
@@ -1096,7 +1133,7 @@ void AwContents::OnWebLayoutContentsSizeChanged(
 }
 
 jlong AwContents::CapturePicture(JNIEnv* env,
-                                 jobject obj,
+                                 const JavaParamRef<jobject>& obj,
                                  int width,
                                  int height) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ -1105,7 +1142,7 @@ jlong AwContents::CapturePicture(JNIEnv* env,
 }
 
 void AwContents::EnableOnNewPicture(JNIEnv* env,
-                                    jobject obj,
+                                    const JavaParamRef<jobject>& obj,
                                     jboolean enabled) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.EnableOnNewPicture(enabled);
@@ -1126,7 +1163,10 @@ void InvokeVisualStateCallback(const JavaObjectWeakGlobalRef& java_ref,
 }  // namespace
 
 void AwContents::InsertVisualStateCallback(
-    JNIEnv* env, jobject obj, jlong request_id, jobject callback) {
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    jlong request_id,
+    const JavaParamRef<jobject>& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ScopedJavaGlobalRef<jobject>* j_callback = new ScopedJavaGlobalRef<jobject>();
   j_callback->Reset(env, callback);
@@ -1135,13 +1175,16 @@ void AwContents::InsertVisualStateCallback(
                  base::Owned(j_callback)));
 }
 
-void AwContents::ClearView(JNIEnv* env, jobject obj) {
+void AwContents::ClearView(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.ClearView();
 }
 
-void AwContents::SetExtraHeadersForUrl(JNIEnv* env, jobject obj,
-                                       jstring url, jstring jextra_headers) {
+void AwContents::SetExtraHeadersForUrl(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jstring>& url,
+    const JavaParamRef<jstring>& jextra_headers) {
   std::string extra_headers;
   if (jextra_headers)
     extra_headers = ConvertJavaStringToUTF8(env, jextra_headers);
@@ -1153,14 +1196,14 @@ void AwContents::SetExtraHeadersForUrl(JNIEnv* env, jobject obj,
 }
 
 void AwContents::SetJsOnlineProperty(JNIEnv* env,
-                                     jobject obj,
+                                     const JavaParamRef<jobject>& obj,
                                      jboolean network_up) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   render_view_host_ext_->SetJsOnlineProperty(network_up);
 }
 
 void AwContents::TrimMemory(JNIEnv* env,
-                            jobject obj,
+                            const JavaParamRef<jobject>& obj,
                             jint level,
                             jboolean visible) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ -1169,10 +1212,12 @@ void AwContents::TrimMemory(JNIEnv* env,
 
 // TODO(sgurun) add support for posting a frame whose name is known (only
 //               main frame is supported at this time, see crbug.com/389721)
-void AwContents::PostMessageToFrame(JNIEnv* env, jobject obj,
-    jstring frame_name, jstring message, jstring target_origin,
-    jintArray sent_ports) {
-
+void AwContents::PostMessageToFrame(JNIEnv* env,
+                                    const JavaParamRef<jobject>& obj,
+                                    const JavaParamRef<jstring>& frame_name,
+                                    const JavaParamRef<jstring>& message,
+                                    const JavaParamRef<jstring>& target_origin,
+                                    const JavaParamRef<jintArray>& sent_ports) {
   // Use an empty source origin for android webview.
   base::string16 source_origin;
   base::string16 j_target_origin(ConvertJavaStringToUTF16(env, target_origin));
@@ -1211,20 +1256,23 @@ AwContents::GetMessagePortMessageFilter() {
   return message_port_message_filter_;
 }
 
-void AwContents::CreateMessageChannel(JNIEnv* env, jobject obj,
-    jobjectArray ports) {
-
+void AwContents::CreateMessageChannel(JNIEnv* env,
+                                      const JavaParamRef<jobject>& obj,
+                                      const JavaParamRef<jobjectArray>& ports) {
   AwMessagePortServiceImpl::GetInstance()->CreateMessageChannel(env, ports,
       GetMessagePortMessageFilter());
 }
 
-void AwContents::GrantFileSchemeAccesstoChildProcess(JNIEnv* env, jobject obj) {
+void AwContents::GrantFileSchemeAccesstoChildProcess(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   content::ChildProcessSecurityPolicy::GetInstance()->GrantScheme(
       web_contents_->GetRenderProcessHost()->GetID(), url::kFileScheme);
 }
 
-void AwContents::ResumeLoadingCreatedPopupWebContents(JNIEnv* env,
-                                                      jobject obj) {
+void AwContents::ResumeLoadingCreatedPopupWebContents(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   web_contents_->ResumeLoadingCreatedWebContents();
 }
 
diff --git a/android_webview/native/aw_contents.h b/android_webview/native/aw_contents.h
index af9e881..22fe1b1 100644
--- a/android_webview/native/aw_contents.h
+++ b/android_webview/native/aw_contents.h
@@ -86,45 +86,85 @@ class AwContents : public FindHelper::Listener,
   void SetOffscreenPreRaster(bool enabled);
 
   // Methods called from Java.
-  void SetJavaPeers(JNIEnv* env,
-                    jobject obj,
-                    jobject aw_contents,
-                    jobject web_contents_delegate,
-                    jobject contents_client_bridge,
-                    jobject io_thread_client,
-                    jobject intercept_navigation_delegate);
-  base::android::ScopedJavaLocalRef<jobject> GetWebContents(JNIEnv* env,
-                                                            jobject obj);
-
-  void Destroy(JNIEnv* env, jobject obj);
-  void DocumentHasImages(JNIEnv* env, jobject obj, jobject message);
-  void GenerateMHTML(JNIEnv* env, jobject obj, jstring jpath, jobject callback);
-  void CreatePdfExporter(JNIEnv* env, jobject obj, jobject pdfExporter);
-  void AddVisitedLinks(JNIEnv* env, jobject obj, jobjectArray jvisited_links);
+  void SetJavaPeers(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobject>& aw_contents,
+      const base::android::JavaParamRef<jobject>& web_contents_delegate,
+      const base::android::JavaParamRef<jobject>& contents_client_bridge,
+      const base::android::JavaParamRef<jobject>& io_thread_client,
+      const base::android::JavaParamRef<jobject>&
+          intercept_navigation_delegate);
+  base::android::ScopedJavaLocalRef<jobject> GetWebContents(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void DocumentHasImages(JNIEnv* env,
+                         const base::android::JavaParamRef<jobject>& obj,
+                         const base::android::JavaParamRef<jobject>& message);
+  void GenerateMHTML(JNIEnv* env,
+                     const base::android::JavaParamRef<jobject>& obj,
+                     const base::android::JavaParamRef<jstring>& jpath,
+                     const base::android::JavaParamRef<jobject>& callback);
+  void CreatePdfExporter(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobject>& pdfExporter);
+  void AddVisitedLinks(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobjectArray>& jvisited_links);
   base::android::ScopedJavaLocalRef<jbyteArray> GetCertificate(
-      JNIEnv* env, jobject obj);
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
   void RequestNewHitTestDataAt(JNIEnv* env,
-                               jobject obj,
+                               const base::android::JavaParamRef<jobject>& obj,
                                jfloat x,
                                jfloat y,
                                jfloat touch_major);
-  void UpdateLastHitTestData(JNIEnv* env, jobject obj);
-  void OnSizeChanged(JNIEnv* env, jobject obj, int w, int h, int ow, int oh);
-  void SetViewVisibility(JNIEnv* env, jobject obj, bool visible);
-  void SetWindowVisibility(JNIEnv* env, jobject obj, bool visible);
-  void SetIsPaused(JNIEnv* env, jobject obj, bool paused);
-  void OnAttachedToWindow(JNIEnv* env, jobject obj, int w, int h);
-  void OnDetachedFromWindow(JNIEnv* env, jobject obj);
-  bool IsVisible(JNIEnv* env, jobject obj);
+  void UpdateLastHitTestData(JNIEnv* env,
+                             const base::android::JavaParamRef<jobject>& obj);
+  void OnSizeChanged(JNIEnv* env,
+                     const base::android::JavaParamRef<jobject>& obj,
+                     int w,
+                     int h,
+                     int ow,
+                     int oh);
+  void SetViewVisibility(JNIEnv* env,
+                         const base::android::JavaParamRef<jobject>& obj,
+                         bool visible);
+  void SetWindowVisibility(JNIEnv* env,
+                           const base::android::JavaParamRef<jobject>& obj,
+                           bool visible);
+  void SetIsPaused(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj,
+                   bool paused);
+  void OnAttachedToWindow(JNIEnv* env,
+                          const base::android::JavaParamRef<jobject>& obj,
+                          int w,
+                          int h);
+  void OnDetachedFromWindow(JNIEnv* env,
+                            const base::android::JavaParamRef<jobject>& obj);
+  bool IsVisible(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
   base::android::ScopedJavaLocalRef<jbyteArray> GetOpaqueState(
-      JNIEnv* env, jobject obj);
-  jboolean RestoreFromOpaqueState(JNIEnv* env, jobject obj, jbyteArray state);
-  void FocusFirstNode(JNIEnv* env, jobject obj);
-  void SetBackgroundColor(JNIEnv* env, jobject obj, jint color);
-  void OnComputeScroll(JNIEnv* env, jobject obj, jlong animation_time_millis);
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  jboolean RestoreFromOpaqueState(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jbyteArray>& state);
+  void FocusFirstNode(JNIEnv* env,
+                      const base::android::JavaParamRef<jobject>& obj);
+  void SetBackgroundColor(JNIEnv* env,
+                          const base::android::JavaParamRef<jobject>& obj,
+                          jint color);
+  void OnComputeScroll(JNIEnv* env,
+                       const base::android::JavaParamRef<jobject>& obj,
+                       jlong animation_time_millis);
   bool OnDraw(JNIEnv* env,
-              jobject obj,
-              jobject canvas,
+              const base::android::JavaParamRef<jobject>& obj,
+              const base::android::JavaParamRef<jobject>& canvas,
               jboolean is_hardware_accelerated,
               jint scroll_x,
               jint scroll_y,
@@ -132,21 +172,32 @@ class AwContents : public FindHelper::Listener,
               jint visible_top,
               jint visible_right,
               jint visible_bottom);
-  jlong GetAwDrawGLViewContext(JNIEnv* env, jobject obj);
-  jlong CapturePicture(JNIEnv* env, jobject obj, int width, int height);
-  void EnableOnNewPicture(JNIEnv* env, jobject obj, jboolean enabled);
-  void InsertVisualStateCallback(JNIEnv* env,
-                        jobject obj,
-                        jlong request_id,
-                        jobject callback);
-  void ClearView(JNIEnv* env, jobject obj);
-  void SetExtraHeadersForUrl(JNIEnv* env, jobject obj,
-                             jstring url, jstring extra_headers);
-
-  void InvokeGeolocationCallback(JNIEnv* env,
-                                 jobject obj,
-                                 jboolean value,
-                                 jstring origin);
+  jlong GetAwDrawGLViewContext(JNIEnv* env,
+                               const base::android::JavaParamRef<jobject>& obj);
+  jlong CapturePicture(JNIEnv* env,
+                       const base::android::JavaParamRef<jobject>& obj,
+                       int width,
+                       int height);
+  void EnableOnNewPicture(JNIEnv* env,
+                          const base::android::JavaParamRef<jobject>& obj,
+                          jboolean enabled);
+  void InsertVisualStateCallback(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jlong request_id,
+      const base::android::JavaParamRef<jobject>& callback);
+  void ClearView(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void SetExtraHeadersForUrl(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& url,
+      const base::android::JavaParamRef<jstring>& extra_headers);
+
+  void InvokeGeolocationCallback(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jboolean value,
+      const base::android::JavaParamRef<jstring>& origin);
 
   // PermissionRequestHandlerClient implementation.
   void OnPermissionRequest(base::android::ScopedJavaLocalRef<jobject> j_request,
@@ -157,10 +208,11 @@ class AwContents : public FindHelper::Listener,
     return permission_request_handler_.get();
   }
 
-  void PreauthorizePermission(JNIEnv* env,
-                              jobject obj,
-                              jstring origin,
-                              jlong resources);
+  void PreauthorizePermission(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& origin,
+      jlong resources);
 
   // AwBrowserPermissionRequestDelegate implementation.
   void RequestProtectedMediaIdentifierPermission(
@@ -178,9 +230,14 @@ class AwContents : public FindHelper::Listener,
   void CancelMIDISysexPermissionRequests(const GURL& origin) override;
 
   // Find-in-page API and related methods.
-  void FindAllAsync(JNIEnv* env, jobject obj, jstring search_string);
-  void FindNext(JNIEnv* env, jobject obj, jboolean forward);
-  void ClearMatches(JNIEnv* env, jobject obj);
+  void FindAllAsync(JNIEnv* env,
+                    const base::android::JavaParamRef<jobject>& obj,
+                    const base::android::JavaParamRef<jstring>& search_string);
+  void FindNext(JNIEnv* env,
+                const base::android::JavaParamRef<jobject>& obj,
+                jboolean forward);
+  void ClearMatches(JNIEnv* env,
+                    const base::android::JavaParamRef<jobject>& obj);
   FindHelper* GetFindHelper();
 
   // Per WebView Cookie Policy
@@ -218,33 +275,58 @@ class AwContents : public FindHelper::Listener,
   void ParentDrawConstraintsUpdated(
       const ParentCompositorDrawConstraints& draw_constraints) override {}
 
-  void ClearCache(JNIEnv* env, jobject obj, jboolean include_disk_files);
+  void ClearCache(JNIEnv* env,
+                  const base::android::JavaParamRef<jobject>& obj,
+                  jboolean include_disk_files);
   void SetPendingWebContentsForPopup(scoped_ptr<content::WebContents> pending);
-  jlong ReleasePopupAwContents(JNIEnv* env, jobject obj);
+  jlong ReleasePopupAwContents(JNIEnv* env,
+                               const base::android::JavaParamRef<jobject>& obj);
 
-  void ScrollTo(JNIEnv* env, jobject obj, jint x, jint y);
+  void ScrollTo(JNIEnv* env,
+                const base::android::JavaParamRef<jobject>& obj,
+                jint x,
+                jint y);
   void SmoothScroll(JNIEnv* env,
-                    jobject obj,
+                    const base::android::JavaParamRef<jobject>& obj,
                     jint target_x,
                     jint target_y,
                     jlong duration_ms);
-  void SetDipScale(JNIEnv* env, jobject obj, jfloat dip_scale);
+  void SetDipScale(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj,
+                   jfloat dip_scale);
   void SetSaveFormData(bool enabled);
 
   // Sets the java client
   void SetAwAutofillClient(jobject client);
 
-  void SetJsOnlineProperty(JNIEnv* env, jobject obj, jboolean network_up);
-  void TrimMemory(JNIEnv* env, jobject obj, jint level, jboolean visible);
+  void SetJsOnlineProperty(JNIEnv* env,
+                           const base::android::JavaParamRef<jobject>& obj,
+                           jboolean network_up);
+  void TrimMemory(JNIEnv* env,
+                  const base::android::JavaParamRef<jobject>& obj,
+                  jint level,
+                  jboolean visible);
 
   scoped_refptr<AwMessagePortMessageFilter> GetMessagePortMessageFilter();
-  void PostMessageToFrame(JNIEnv* env, jobject obj, jstring frame_id,
-      jstring message, jstring target_origin, jintArray sent_ports);
-  void CreateMessageChannel(JNIEnv* env, jobject obj, jobjectArray ports);
-
-  void GrantFileSchemeAccesstoChildProcess(JNIEnv* env, jobject obj);
-
-  void ResumeLoadingCreatedPopupWebContents(JNIEnv* env, jobject obj);
+  void PostMessageToFrame(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& frame_id,
+      const base::android::JavaParamRef<jstring>& message,
+      const base::android::JavaParamRef<jstring>& target_origin,
+      const base::android::JavaParamRef<jintArray>& sent_ports);
+  void CreateMessageChannel(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobjectArray>& ports);
+
+  void GrantFileSchemeAccesstoChildProcess(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+
+  void ResumeLoadingCreatedPopupWebContents(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
 
  private:
   void InitAutofillIfNecessary(bool enabled);
diff --git a/android_webview/native/aw_contents_client_bridge.cc b/android_webview/native/aw_contents_client_bridge.cc
index 9e570af..2dae8f5 100644
--- a/android_webview/native/aw_contents_client_bridge.cc
+++ b/android_webview/native/aw_contents_client_bridge.cc
@@ -108,8 +108,10 @@ void AwContentsClientBridge::AllowCertificateError(
   }
 }
 
-void AwContentsClientBridge::ProceedSslError(JNIEnv* env, jobject obj,
-                                             jboolean proceed, jint id) {
+void AwContentsClientBridge::ProceedSslError(JNIEnv* env,
+                                             const JavaRef<jobject>& obj,
+                                             jboolean proceed,
+                                             jint id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   CertErrorCallback* callback = pending_cert_error_callbacks_.Lookup(id);
   if (!callback || callback->is_null()) {
@@ -196,17 +198,17 @@ void AwContentsClientBridge::SelectClientCertificate(
 // chrome/browser/ui/android/ssl_client_certificate_request.cc
 void AwContentsClientBridge::ProvideClientCertificateResponse(
     JNIEnv* env,
-    jobject obj,
+    const JavaRef<jobject>& obj,
     int request_id,
-    jobjectArray encoded_chain_ref,
-    jobject private_key_ref) {
+    const JavaRef<jobjectArray>& encoded_chain_ref,
+    const JavaRef<jobject>& private_key_ref) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   content::ClientCertificateDelegate* delegate =
       pending_client_cert_request_delegates_.Lookup(request_id);
   DCHECK(delegate);
 
-  if (encoded_chain_ref == NULL || private_key_ref == NULL) {
+  if (encoded_chain_ref.is_null() || private_key_ref.is_null()) {
     LOG(ERROR) << "No client certificate selected";
     pending_client_cert_request_delegates_.Remove(request_id);
     delegate->ContinueWithCertificate(nullptr);
@@ -222,9 +224,9 @@ void AwContentsClientBridge::ProvideClientCertificateResponse(
 
   // Convert the encoded chain to a vector of strings.
   std::vector<std::string> encoded_chain_strings;
-  if (encoded_chain_ref) {
+  if (!encoded_chain_ref.is_null()) {
     base::android::JavaArrayOfByteArrayToStringVector(
-        env, encoded_chain_ref, &encoded_chain_strings);
+        env, encoded_chain_ref.obj(), &encoded_chain_strings);
   }
 
   std::vector<base::StringPiece> encoded_chain;
@@ -241,7 +243,7 @@ void AwContentsClientBridge::ProvideClientCertificateResponse(
 
   // Create an EVP_PKEY wrapper for the private key JNI reference.
   crypto::ScopedEVP_PKEY private_key(
-      net::android::GetOpenSSLPrivateKeyWrapper(private_key_ref));
+      net::android::GetOpenSSLPrivateKeyWrapper(private_key_ref.obj()));
   if (!private_key.get()) {
     LOG(ERROR) << "Could not create OpenSSL wrapper for private key";
     return;
@@ -341,9 +343,9 @@ void AwContentsClientBridge::RunBeforeUnloadDialog(
 }
 
 void AwContentsClientBridge::ConfirmJsResult(JNIEnv* env,
-                                             jobject,
+                                             const JavaRef<jobject>&,
                                              int id,
-                                             jstring prompt) {
+                                             const JavaRef<jstring>& prompt) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   content::JavaScriptDialogManager::DialogClosedCallback* callback =
       pending_js_dialog_callbacks_.Lookup(id);
@@ -352,14 +354,16 @@ void AwContentsClientBridge::ConfirmJsResult(JNIEnv* env,
     return;
   }
   base::string16 prompt_text;
-  if (prompt) {
+  if (!prompt.is_null()) {
     prompt_text = ConvertJavaStringToUTF16(env, prompt);
   }
   callback->Run(true, prompt_text);
   pending_js_dialog_callbacks_.Remove(id);
 }
 
-void AwContentsClientBridge::CancelJsResult(JNIEnv*, jobject, int id) {
+void AwContentsClientBridge::CancelJsResult(JNIEnv*,
+                                            const JavaRef<jobject>&,
+                                            int id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   content::JavaScriptDialogManager::DialogClosedCallback* callback =
       pending_js_dialog_callbacks_.Lookup(id);
diff --git a/android_webview/native/aw_contents_client_bridge.h b/android_webview/native/aw_contents_client_bridge.h
index 74f13e0..5372fb0 100644
--- a/android_webview/native/aw_contents_client_bridge.h
+++ b/android_webview/native/aw_contents_client_bridge.h
@@ -56,12 +56,21 @@ class AwContentsClientBridge : public AwContentsClientBridgeBase {
       override;
 
   // Methods called from Java.
-  void ProceedSslError(JNIEnv* env, jobject obj, jboolean proceed, jint id);
-  void ProvideClientCertificateResponse(JNIEnv* env, jobject object,
-      jint request_id, jobjectArray encoded_chain_ref,
-      jobject private_key_ref);
-  void ConfirmJsResult(JNIEnv*, jobject, int id, jstring prompt);
-  void CancelJsResult(JNIEnv*, jobject, int id);
+  void ProceedSslError(JNIEnv* env,
+                       const base::android::JavaRef<jobject>& obj,
+                       jboolean proceed,
+                       jint id);
+  void ProvideClientCertificateResponse(
+      JNIEnv* env,
+      const base::android::JavaRef<jobject>& object,
+      jint request_id,
+      const base::android::JavaRef<jobjectArray>& encoded_chain_ref,
+      const base::android::JavaRef<jobject>& private_key_ref);
+  void ConfirmJsResult(JNIEnv*,
+                       const base::android::JavaRef<jobject>&,
+                       int id,
+                       const base::android::JavaRef<jstring>& prompt);
+  void CancelJsResult(JNIEnv*, const base::android::JavaRef<jobject>&, int id);
 
  private:
   void HandleErrorInClientCertificateResponse(int id);
diff --git a/android_webview/native/aw_contents_client_bridge_unittest.cc b/android_webview/native/aw_contents_client_bridge_unittest.cc
index 5f19a52..e685d0b 100644
--- a/android_webview/native/aw_contents_client_bridge_unittest.cc
+++ b/android_webview/native/aw_contents_client_bridge_unittest.cc
@@ -129,10 +129,10 @@ TEST_F(AwContentsClientBridgeTest,
   bridge_->SelectClientCertificate(
       cert_request_info_.get(),
       make_scoped_ptr(new TestClientCertificateDelegate(this)));
-  bridge_->ProvideClientCertificateResponse(env_, jbridge_.obj(),
+  bridge_->ProvideClientCertificateResponse(
+      env_, jbridge_,
       Java_MockAwContentsClientBridge_getRequestId(env_, jbridge_.obj()),
-      Java_MockAwContentsClientBridge_createTestCertChain(
-          env_, jbridge_.obj()).obj(),
+      Java_MockAwContentsClientBridge_createTestCertChain(env_, jbridge_.obj()),
       nullptr);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(nullptr, selected_cert_);
@@ -150,8 +150,8 @@ TEST_F(AwContentsClientBridgeTest,
       make_scoped_ptr(new TestClientCertificateDelegate(this)));
   int requestId =
     Java_MockAwContentsClientBridge_getRequestId(env_, jbridge_.obj());
-  bridge_->ProvideClientCertificateResponse(
-      env_, jbridge_.obj(), requestId, nullptr, nullptr);
+  bridge_->ProvideClientCertificateResponse(env_, jbridge_, requestId, nullptr,
+                                            nullptr);
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(nullptr, selected_cert_);
   EXPECT_EQ(1, cert_selected_callbacks_);
diff --git a/android_webview/native/aw_http_auth_handler.cc b/android_webview/native/aw_http_auth_handler.cc
index 700270a..8f4293b 100644
--- a/android_webview/native/aw_http_auth_handler.cc
+++ b/android_webview/native/aw_http_auth_handler.cc
@@ -38,9 +38,9 @@ AwHttpAuthHandler:: ~AwHttpAuthHandler() {
 }
 
 void AwHttpAuthHandler::Proceed(JNIEnv* env,
-                                jobject obj,
-                                jstring user,
-                                jstring password) {
+                                const JavaParamRef<jobject>& obj,
+                                const JavaParamRef<jstring>& user,
+                                const JavaParamRef<jstring>& password) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (login_delegate_.get()) {
     login_delegate_->Proceed(ConvertJavaStringToUTF16(env, user),
@@ -49,7 +49,7 @@ void AwHttpAuthHandler::Proceed(JNIEnv* env,
   }
 }
 
-void AwHttpAuthHandler::Cancel(JNIEnv* env, jobject obj) {
+void AwHttpAuthHandler::Cancel(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (login_delegate_.get()) {
     login_delegate_->Cancel();
diff --git a/android_webview/native/aw_http_auth_handler.h b/android_webview/native/aw_http_auth_handler.h
index 79b7406..09f6ed1 100644
--- a/android_webview/native/aw_http_auth_handler.h
+++ b/android_webview/native/aw_http_auth_handler.h
@@ -37,8 +37,11 @@ class AwHttpAuthHandler : public AwHttpAuthHandlerBase {
   // from AwHttpAuthHandler
   bool HandleOnUIThread(content::WebContents* web_contents) override;
 
-  void Proceed(JNIEnv* env, jobject obj, jstring username, jstring password);
-  void Cancel(JNIEnv* env, jobject obj);
+  void Proceed(JNIEnv* env,
+               const base::android::JavaParamRef<jobject>& obj,
+               const base::android::JavaParamRef<jstring>& username,
+               const base::android::JavaParamRef<jstring>& password);
+  void Cancel(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
 
  private:
   scoped_refptr<AwLoginDelegate> login_delegate_;
diff --git a/android_webview/native/aw_message_port_service_impl.cc b/android_webview/native/aw_message_port_service_impl.cc
index cbbe282..65f7bb0 100644
--- a/android_webview/native/aw_message_port_service_impl.cc
+++ b/android_webview/native/aw_message_port_service_impl.cc
@@ -122,8 +122,12 @@ void AwMessagePortServiceImpl::OnMessagePortMessageFilterClosing(
   }
 }
 
-void AwMessagePortServiceImpl::PostAppToWebMessage(JNIEnv* env, jobject obj,
-    int sender_id, jstring message, jintArray sent_ports) {
+void AwMessagePortServiceImpl::PostAppToWebMessage(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    int sender_id,
+    const JavaParamRef<jstring>& message,
+    const JavaParamRef<jintArray>& sent_ports) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   base::string16* j_message = new base::string16;
   ConvertJavaStringToUTF16(env, message, j_message);
@@ -145,8 +149,9 @@ void AwMessagePortServiceImpl::PostAppToWebMessage(JNIEnv* env, jobject obj,
 // it is possible that messages are still queued in the renderer process
 // waiting for a conversion. Instead, it sends a special message with
 // a flag which indicates that this message port should be closed.
-void AwMessagePortServiceImpl::ClosePort(JNIEnv* env, jobject obj,
-    int message_port_id) {
+void AwMessagePortServiceImpl::ClosePort(JNIEnv* env,
+                                         const JavaParamRef<jobject>& obj,
+                                         int message_port_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   BrowserThread::PostTask(
       BrowserThread::IO,
@@ -156,8 +161,9 @@ void AwMessagePortServiceImpl::ClosePort(JNIEnv* env, jobject obj,
                  message_port_id));
 }
 
-void AwMessagePortServiceImpl::ReleaseMessages(JNIEnv* env, jobject obj,
-    int message_port_id) {
+void AwMessagePortServiceImpl::ReleaseMessages(JNIEnv* env,
+                                               const JavaParamRef<jobject>& obj,
+                                               int message_port_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   BrowserThread::PostTask(
       BrowserThread::IO,
diff --git a/android_webview/native/aw_message_port_service_impl.h b/android_webview/native/aw_message_port_service_impl.h
index 7f42421..2ee31b4 100644
--- a/android_webview/native/aw_message_port_service_impl.h
+++ b/android_webview/native/aw_message_port_service_impl.h
@@ -42,10 +42,18 @@ class AwMessagePortServiceImpl : public AwMessagePortService {
   void CleanupPort(int message_port_id) override;
 
   // Methods called from Java.
-  void PostAppToWebMessage(JNIEnv* env, jobject object, int sender_id,
-      jstring message, jintArray sent_ports);
-  void ClosePort(JNIEnv* env, jobject object, int message_port_id);
-  void ReleaseMessages(JNIEnv* env, jobject object, int message_port_id);
+  void PostAppToWebMessage(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& object,
+      int sender_id,
+      const base::android::JavaParamRef<jstring>& message,
+      const base::android::JavaParamRef<jintArray>& sent_ports);
+  void ClosePort(JNIEnv* env,
+                 const base::android::JavaParamRef<jobject>& object,
+                 int message_port_id);
+  void ReleaseMessages(JNIEnv* env,
+                       const base::android::JavaParamRef<jobject>& object,
+                       int message_port_id);
 
   void RemoveSentPorts(const std::vector<int>& sent_ports);
 
diff --git a/android_webview/native/aw_pdf_exporter.cc b/android_webview/native/aw_pdf_exporter.cc
index 48fa9f9..af08f1f 100644
--- a/android_webview/native/aw_pdf_exporter.cc
+++ b/android_webview/native/aw_pdf_exporter.cc
@@ -33,9 +33,9 @@ AwPdfExporter::~AwPdfExporter() {
 }
 
 void AwPdfExporter::ExportToPdf(JNIEnv* env,
-                                jobject obj,
+                                const JavaParamRef<jobject>& obj,
                                 int fd,
-                                jobject cancel_signal) {
+                                const JavaParamRef<jobject>& cancel_signal) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   printing::PrintSettings print_settings;
   InitPdfSettings(env, obj, print_settings);
diff --git a/android_webview/native/aw_pdf_exporter.h b/android_webview/native/aw_pdf_exporter.h
index f2513f8..2b44a85 100644
--- a/android_webview/native/aw_pdf_exporter.h
+++ b/android_webview/native/aw_pdf_exporter.h
@@ -31,9 +31,9 @@ class AwPdfExporter {
   ~AwPdfExporter();
 
   void ExportToPdf(JNIEnv* env,
-                   jobject obj,
+                   const base::android::JavaParamRef<jobject>& obj,
                    int fd,
-                   jobject cancel_signal);
+                   const base::android::JavaParamRef<jobject>& cancel_signal);
 
  private:
   void InitPdfSettings(JNIEnv* env,
diff --git a/android_webview/native/aw_picture.cc b/android_webview/native/aw_picture.cc
index a46be2c..6c98d3d 100644
--- a/android_webview/native/aw_picture.cc
+++ b/android_webview/native/aw_picture.cc
@@ -18,19 +18,21 @@ AwPicture::AwPicture(skia::RefPtr<SkPicture> picture)
 
 AwPicture::~AwPicture() {}
 
-void AwPicture::Destroy(JNIEnv* env, jobject obj) {
+void AwPicture::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
-jint AwPicture::GetWidth(JNIEnv* env, jobject obj) {
+jint AwPicture::GetWidth(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   return picture_->cullRect().roundOut().width();
 }
 
-jint AwPicture::GetHeight(JNIEnv* env, jobject obj) {
+jint AwPicture::GetHeight(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   return picture_->cullRect().roundOut().height();
 }
 
-void AwPicture::Draw(JNIEnv* env, jobject obj, jobject canvas) {
+void AwPicture::Draw(JNIEnv* env,
+                     const JavaParamRef<jobject>& obj,
+                     const JavaParamRef<jobject>& canvas) {
   const SkIRect bounds = picture_->cullRect().roundOut();
   scoped_ptr<SoftwareCanvasHolder> canvas_holder = SoftwareCanvasHolder::Create(
       canvas, gfx::Vector2d(), gfx::Size(bounds.width(), bounds.height()),
diff --git a/android_webview/native/aw_picture.h b/android_webview/native/aw_picture.h
index fc4d1ec..bc129e5 100644
--- a/android_webview/native/aw_picture.h
+++ b/android_webview/native/aw_picture.h
@@ -23,10 +23,12 @@ class AwPicture {
   ~AwPicture();
 
   // Methods called from Java.
-  void Destroy(JNIEnv* env, jobject obj);
-  jint GetWidth(JNIEnv* env, jobject obj);
-  jint GetHeight(JNIEnv* env, jobject obj);
-  void Draw(JNIEnv* env, jobject obj, jobject canvas);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  jint GetWidth(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  jint GetHeight(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void Draw(JNIEnv* env,
+            const base::android::JavaParamRef<jobject>& obj,
+            const base::android::JavaParamRef<jobject>& canvas);
 
  private:
   skia::RefPtr<SkPicture> picture_;
diff --git a/android_webview/native/aw_quota_manager_bridge_impl.cc b/android_webview/native/aw_quota_manager_bridge_impl.cc
index abf791e..d4ae0cd 100644
--- a/android_webview/native/aw_quota_manager_bridge_impl.cc
+++ b/android_webview/native/aw_quota_manager_bridge_impl.cc
@@ -180,7 +180,8 @@ AwQuotaManagerBridgeImpl::AwQuotaManagerBridgeImpl(
 
 AwQuotaManagerBridgeImpl::~AwQuotaManagerBridgeImpl() {}
 
-void AwQuotaManagerBridgeImpl::Init(JNIEnv* env, jobject object) {
+void AwQuotaManagerBridgeImpl::Init(JNIEnv* env,
+                                    const JavaParamRef<jobject>& object) {
   java_ref_ = JavaObjectWeakGlobalRef(env, object);
 }
 
@@ -202,7 +203,9 @@ QuotaManager* AwQuotaManagerBridgeImpl::GetQuotaManager() const {
   return quota_manager;
 }
 
-void AwQuotaManagerBridgeImpl::DeleteAllData(JNIEnv* env, jobject object) {
+void AwQuotaManagerBridgeImpl::DeleteAllData(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& object) {
   RunOnUIThread(base::Bind(&AwQuotaManagerBridgeImpl::DeleteAllDataOnUiThread,
                            this));
 }
@@ -222,7 +225,9 @@ void AwQuotaManagerBridgeImpl::DeleteAllDataOnUiThread() {
 }
 
 void AwQuotaManagerBridgeImpl::DeleteOrigin(
-    JNIEnv* env, jobject object, jstring origin) {
+    JNIEnv* env,
+    const JavaParamRef<jobject>& object,
+    const JavaParamRef<jstring>& origin) {
   base::string16 origin_string(
       base::android::ConvertJavaStringToUTF16(env, origin));
   RunOnUIThread(base::Bind(&AwQuotaManagerBridgeImpl::DeleteOriginOnUiThread,
@@ -246,8 +251,9 @@ void AwQuotaManagerBridgeImpl::DeleteOriginOnUiThread(
       base::Bind(&base::DoNothing));
 }
 
-void AwQuotaManagerBridgeImpl::GetOrigins(
-    JNIEnv* env, jobject object, jint callback_id) {
+void AwQuotaManagerBridgeImpl::GetOrigins(JNIEnv* env,
+                                          const JavaParamRef<jobject>& object,
+                                          jint callback_id) {
   RunOnUIThread(base::Bind(&AwQuotaManagerBridgeImpl::GetOriginsOnUiThread,
                            this,
                            callback_id));
@@ -305,8 +311,9 @@ void OnUsageAndQuotaObtained(
 } // namespace
 
 void AwQuotaManagerBridgeImpl::GetUsageAndQuotaForOrigin(
-    JNIEnv* env, jobject object,
-    jstring origin,
+    JNIEnv* env,
+    const JavaParamRef<jobject>& object,
+    const JavaParamRef<jstring>& origin,
     jint callback_id,
     bool is_quota) {
   base::string16 origin_string(
diff --git a/android_webview/native/aw_quota_manager_bridge_impl.h b/android_webview/native/aw_quota_manager_bridge_impl.h
index dc7f20f3..530705d 100644
--- a/android_webview/native/aw_quota_manager_bridge_impl.h
+++ b/android_webview/native/aw_quota_manager_bridge_impl.h
@@ -37,15 +37,21 @@ class AwQuotaManagerBridgeImpl : public AwQuotaManagerBridge {
       AwBrowserContext* browser_context);
 
   // Called by Java.
-  void Init(JNIEnv* env, jobject object);
-  void DeleteAllData(JNIEnv* env, jobject object);
-  void DeleteOrigin(JNIEnv* env, jobject object, jstring origin);
-  void GetOrigins(JNIEnv* env, jobject object, jint callback_id);
-  void GetUsageAndQuotaForOrigin(JNIEnv* env,
-                                 jobject object,
-                                 jstring origin,
-                                 jint callback_id,
-                                 bool is_quota);
+  void Init(JNIEnv* env, const base::android::JavaParamRef<jobject>& object);
+  void DeleteAllData(JNIEnv* env,
+                     const base::android::JavaParamRef<jobject>& object);
+  void DeleteOrigin(JNIEnv* env,
+                    const base::android::JavaParamRef<jobject>& object,
+                    const base::android::JavaParamRef<jstring>& origin);
+  void GetOrigins(JNIEnv* env,
+                  const base::android::JavaParamRef<jobject>& object,
+                  jint callback_id);
+  void GetUsageAndQuotaForOrigin(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& object,
+      const base::android::JavaParamRef<jstring>& origin,
+      jint callback_id,
+      bool is_quota);
 
   typedef base::Callback<
       void(const std::vector<std::string>& /* origin */,
diff --git a/android_webview/native/aw_settings.cc b/android_webview/native/aw_settings.cc
index 753a9e1..8817abc 100644
--- a/android_webview/native/aw_settings.cc
+++ b/android_webview/native/aw_settings.cc
@@ -93,7 +93,7 @@ AwSettings::~AwSettings() {
                                        reinterpret_cast<intptr_t>(this));
 }
 
-void AwSettings::Destroy(JNIEnv* env, jobject obj) {
+void AwSettings::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
@@ -108,7 +108,8 @@ AwRenderViewHostExt* AwSettings::GetAwRenderViewHostExt() {
   return contents->render_view_host_ext();
 }
 
-void AwSettings::ResetScrollAndScaleState(JNIEnv* env, jobject obj) {
+void AwSettings::ResetScrollAndScaleState(JNIEnv* env,
+                                          const JavaParamRef<jobject>& obj) {
   AwRenderViewHostExt* rvhe = GetAwRenderViewHostExt();
   if (!rvhe) return;
   rvhe->ResetScrollAndScaleState();
@@ -124,7 +125,8 @@ void AwSettings::UpdateEverything() {
   Java_AwSettings_updateEverything(env, obj);
 }
 
-void AwSettings::UpdateEverythingLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateEverythingLocked(JNIEnv* env,
+                                        const JavaParamRef<jobject>& obj) {
   UpdateInitialPageScaleLocked(env, obj);
   UpdateWebkitPreferencesLocked(env, obj);
   UpdateUserAgentLocked(env, obj);
@@ -134,7 +136,8 @@ void AwSettings::UpdateEverythingLocked(JNIEnv* env, jobject obj) {
   UpdateOffscreenPreRasterLocked(env, obj);
 }
 
-void AwSettings::UpdateUserAgentLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateUserAgentLocked(JNIEnv* env,
+                                       const JavaParamRef<jobject>& obj) {
   if (!web_contents()) return;
 
   ScopedJavaLocalRef<jstring> str =
@@ -152,7 +155,9 @@ void AwSettings::UpdateUserAgentLocked(JNIEnv* env, jobject obj) {
     controller.GetEntryAtIndex(i)->SetIsOverridingUserAgent(ua_overidden);
 }
 
-void AwSettings::UpdateWebkitPreferencesLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateWebkitPreferencesLocked(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   if (!web_contents()) return;
   AwRenderViewHostExt* render_view_host_ext = GetAwRenderViewHostExt();
   if (!render_view_host_ext) return;
@@ -163,7 +168,9 @@ void AwSettings::UpdateWebkitPreferencesLocked(JNIEnv* env, jobject obj) {
   render_view_host->OnWebkitPreferencesChanged();
 }
 
-void AwSettings::UpdateInitialPageScaleLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateInitialPageScaleLocked(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   AwRenderViewHostExt* rvhe = GetAwRenderViewHostExt();
   if (!rvhe) return;
 
@@ -178,7 +185,9 @@ void AwSettings::UpdateInitialPageScaleLocked(JNIEnv* env, jobject obj) {
   }
 }
 
-void AwSettings::UpdateFormDataPreferencesLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateFormDataPreferencesLocked(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   if (!web_contents()) return;
   AwContents* contents = AwContents::FromWebContents(web_contents());
   if (!contents) return;
@@ -186,7 +195,9 @@ void AwSettings::UpdateFormDataPreferencesLocked(JNIEnv* env, jobject obj) {
   contents->SetSaveFormData(Java_AwSettings_getSaveFormDataLocked(env, obj));
 }
 
-void AwSettings::UpdateRendererPreferencesLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateRendererPreferencesLocked(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   if (!web_contents()) return;
 
   bool update_prefs = false;
@@ -215,7 +226,9 @@ void AwSettings::UpdateRendererPreferencesLocked(JNIEnv* env, jobject obj) {
     host->SyncRendererPrefs();
 }
 
-void AwSettings::UpdateOffscreenPreRasterLocked(JNIEnv* env, jobject obj) {
+void AwSettings::UpdateOffscreenPreRasterLocked(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
   AwContents* contents = AwContents::FromWebContents(web_contents());
   if (contents) {
     contents->SetOffscreenPreRaster(
@@ -253,8 +266,9 @@ void AwSettings::PopulateWebPreferences(WebPreferences* web_prefs) {
       env, obj, reinterpret_cast<jlong>(web_prefs));
 }
 
-void AwSettings::PopulateWebPreferencesLocked(
-    JNIEnv* env, jobject obj, jlong web_prefs_ptr) {
+void AwSettings::PopulateWebPreferencesLocked(JNIEnv* env,
+                                              const JavaParamRef<jobject>& obj,
+                                              jlong web_prefs_ptr) {
   AwRenderViewHostExt* render_view_host_ext = GetAwRenderViewHostExt();
   if (!render_view_host_ext) return;
 
diff --git a/android_webview/native/aw_settings.h b/android_webview/native/aw_settings.h
index 56b09ad..79d4f75 100644
--- a/android_webview/native/aw_settings.h
+++ b/android_webview/native/aw_settings.h
@@ -29,16 +29,33 @@ class AwSettings : public content::WebContentsObserver {
 
   // Called from Java. Methods with "Locked" suffix require that the settings
   // access lock is held during their execution.
-  void Destroy(JNIEnv* env, jobject obj);
-  void PopulateWebPreferencesLocked(JNIEnv* env, jobject obj, jlong web_prefs);
-  void ResetScrollAndScaleState(JNIEnv* env, jobject obj);
-  void UpdateEverythingLocked(JNIEnv* env, jobject obj);
-  void UpdateInitialPageScaleLocked(JNIEnv* env, jobject obj);
-  void UpdateUserAgentLocked(JNIEnv* env, jobject obj);
-  void UpdateWebkitPreferencesLocked(JNIEnv* env, jobject obj);
-  void UpdateFormDataPreferencesLocked(JNIEnv* env, jobject obj);
-  void UpdateRendererPreferencesLocked(JNIEnv* env, jobject obj);
-  void UpdateOffscreenPreRasterLocked(JNIEnv* env, jobject obj);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void PopulateWebPreferencesLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jlong web_prefs);
+  void ResetScrollAndScaleState(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  void UpdateEverythingLocked(JNIEnv* env,
+                              const base::android::JavaParamRef<jobject>& obj);
+  void UpdateInitialPageScaleLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  void UpdateUserAgentLocked(JNIEnv* env,
+                             const base::android::JavaParamRef<jobject>& obj);
+  void UpdateWebkitPreferencesLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  void UpdateFormDataPreferencesLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  void UpdateRendererPreferencesLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+  void UpdateOffscreenPreRasterLocked(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
 
   void PopulateWebPreferences(content::WebPreferences* web_prefs);
 
diff --git a/android_webview/native/permission/aw_permission_request.cc b/android_webview/native/permission/aw_permission_request.cc
index f25db3e..27f0b5b 100644
--- a/android_webview/native/permission/aw_permission_request.cc
+++ b/android_webview/native/permission/aw_permission_request.cc
@@ -46,7 +46,7 @@ AwPermissionRequest::~AwPermissionRequest() {
 }
 
 void AwPermissionRequest::OnAccept(JNIEnv* env,
-                                   jobject jcaller,
+                                   const JavaParamRef<jobject>& jcaller,
                                    jboolean accept) {
   OnAcceptInternal(accept);
 }
@@ -66,7 +66,8 @@ void AwPermissionRequest::DeleteThis() {
                                          j_request.obj());
 }
 
-void AwPermissionRequest::Destroy(JNIEnv* env, jobject obj) {
+void AwPermissionRequest::Destroy(JNIEnv* env,
+                                  const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
diff --git a/android_webview/native/permission/aw_permission_request.h b/android_webview/native/permission/aw_permission_request.h
index d146538..f016799 100644
--- a/android_webview/native/permission/aw_permission_request.h
+++ b/android_webview/native/permission/aw_permission_request.h
@@ -41,8 +41,10 @@ class AwPermissionRequest {
 
   // Invoked by Java peer when request is processed, |granted| indicates the
   // request was granted or not.
-  void OnAccept(JNIEnv* env, jobject jcaller, jboolean granted);
-  void Destroy(JNIEnv* env, jobject obj);
+  void OnAccept(JNIEnv* env,
+                const base::android::JavaParamRef<jobject>& jcaller,
+                jboolean granted);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
 
   // Return the origin which initiated the request.
   const GURL& GetOrigin();