[chromecast] Fix Android gesture callback scoping

The callback wrapper being local stack allocated means the
asynchronous callback invocation may fail if invoked after the method
returns; this has been causing crash/JNI failure. Switch
to a unique_ptr and move it along.

Additionally the callback argument itself may go out of scope, so
needs to be switched to the correctly scoped JNI handle.

Bug: internal b/162882383
Test: manual on device
Change-Id: I4bb4c87531e9a4b099f61ad9133ad1b3922de4be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364559
Commit-Queue: Ryan Daum <rdaum@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Simeon Anfinrud <sanfin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800086}

chromecast/browser/android/cast_content_window_android.cc

@@ -10,7 +10,6 @@
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/logging.h"
-#include "base/memory/ptr_util.h"
 #include "chromecast/browser/jni_headers/CastContentWindowAndroid_jni.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/events/keycodes/keyboard_code_conversion_android.h"
@@ -48,7 +47,7 @@ class GestureConsumedCallbackWrapper {
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& callback)
       : env_(env), callback_(callback) {
-    class_ = base::android::ScopedJavaLocalRef<jclass>(
+    class_ = base::android::ScopedJavaGlobalRef<jclass>(
         base::android::GetClass(env_, kGestureConsumedCallbackClassName));
     callback_method_id_ =
         base::android::MethodID::Get<base::android::MethodID::TYPE_INSTANCE>(
@@ -57,6 +56,11 @@ class GestureConsumedCallbackWrapper {
             ")V");
   }
 
+  GestureConsumedCallbackWrapper& operator=(
+      const GestureConsumedCallbackWrapper&) = delete;
+  GestureConsumedCallbackWrapper(const GestureConsumedCallbackWrapper&) =
+      delete;
+
   void Invoke(bool handled) {
     jboolean handled_value(handled);
     env_->CallVoidMethod(callback_.obj(), callback_method_id_, handled_value);
@@ -64,11 +68,9 @@ class GestureConsumedCallbackWrapper {
 
  private:
   JNIEnv* env_;
-  const base::android::JavaParamRef<jobject>& callback_;
-  base::android::ScopedJavaLocalRef<jclass> class_;
+  const base::android::ScopedJavaGlobalRef<jobject> callback_;
+  base::android::ScopedJavaGlobalRef<jclass> class_;
   jmethodID callback_method_id_;
-
-  DISALLOW_COPY_AND_ASSIGN(GestureConsumedCallbackWrapper);
 };
 
 }  // namespace
@@ -178,15 +180,16 @@ void CastContentWindowAndroid::ConsumeGesture(
     const base::android::JavaParamRef<jobject>& jcaller,
     int gesture_type,
     const base::android::JavaParamRef<jobject>& callback) {
-  GestureConsumedCallbackWrapper wrapper(env, callback);
+  auto wrapper =
+      std::make_unique<GestureConsumedCallbackWrapper>(env, callback);
   if (delegate_) {
     delegate_->ConsumeGesture(
         static_cast<GestureType>(gesture_type),
         base::BindOnce(&GestureConsumedCallbackWrapper::Invoke,
-                       base::Unretained(&wrapper)));
+                       std::move(wrapper)));
     return;
   }
-  wrapper.Invoke(false);
+  wrapper->Invoke(false);
 }
 
 void CastContentWindowAndroid::OnVisibilityChange(