arc-bridge: Introduce the ArcService class

components/arc/clipboard/arc_clipboard_bridge.cc

 // Copyright 2016 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 "components/arc/clipboard/arc_clipboard_bridge.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_checker.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/clipboard/clipboard_types.h"
 #include "ui/base/clipboard/scoped_clipboard_writer.h"
 
 namespace {
 
 static base::string16 ConvertMojoStringToString16(const mojo::String& input) {
   return base::UTF8ToUTF16(input.get());
 }
 
 static mojo::String ConvertString16ToMojoString(const base::string16& input) {
   return mojo::String(base::UTF16ToUTF8(input));
 }
 
 }  // namespace
 
 namespace arc {
 
-ArcClipboardBridge::ArcClipboardBridge(ArcBridgeService* bridge_service)
-    : bridge_service_(bridge_service), binding_(this) {
-  bridge_service_->AddObserver(this);
+ArcClipboardBridge::ArcClipboardBridge(ArcBridgeService* arc_bridge_service)
+    : arc_bridge_service_(arc_bridge_service), binding_(this) {
+  DCHECK(arc_bridge_service_);
+  arc_bridge_service_->AddObserver(this);
+
+  // If ClipboardInstance was ready before we AddObserver(), we won't get
+  // OnClipboardInstanceReady events. For such case, we have to call it
+  // explicitly.
+  if (arc_bridge_service_->clipboard_instance())
+    OnClipboardInstanceReady();
 }
 
 ArcClipboardBridge::~ArcClipboardBridge() {
   DCHECK(CalledOnValidThread());
-  bridge_service_->RemoveObserver(this);
+  arc_bridge_service_->RemoveObserver(this);
 }
 
 void ArcClipboardBridge::OnClipboardInstanceReady() {
-  ClipboardInstance* clipboard_instance = bridge_service_->clipboard_instance();
+  ClipboardInstance* clipboard_instance =
+      arc_bridge_service_->clipboard_instance();
   if (!clipboard_instance) {
     LOG(ERROR) << "OnClipboardInstanceReady called, "
                << "but no clipboard instance found";
     return;
   }
 
   ClipboardHostPtr host;
   binding_.Bind(mojo::GetProxy(&host));
   clipboard_instance->Init(std::move(host));
 }
 
 void ArcClipboardBridge::SetTextContent(const mojo::String& text) {
   DCHECK(CalledOnValidThread());
   ui::ScopedClipboardWriter writer(ui::CLIPBOARD_TYPE_COPY_PASTE);
   writer.WriteText(ConvertMojoStringToString16(text));
 }
 
 void ArcClipboardBridge::GetTextContent() {
   DCHECK(CalledOnValidThread());
 
   base::string16 text;
   ui::Clipboard* clipboard = ui::Clipboard::GetForCurrentThread();
   clipboard->ReadText(ui::CLIPBOARD_TYPE_COPY_PASTE, &text);
 
-  ClipboardInstance* clipboard_instance = bridge_service_->clipboard_instance();
+  ClipboardInstance* clipboard_instance =
+      arc_bridge_service_->clipboard_instance();
   clipboard_instance->OnGetTextContent(ConvertString16ToMojoString(text));
 }
 
 bool ArcClipboardBridge::CalledOnValidThread() {
   // Make sure access to the Chrome clipboard is happening in the UI thread.
   return thread_checker_.CalledOnValidThread();
 }
 
 }  // namespace arc