Implement SmartText selection.

content/browser/android/context_selection_client.cc

+// Copyright 2017 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 "content/browser/android/context_selection_client.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_string.h"
+#include "base/bind.h"
+#include "content/public/browser/render_frame_host.h"
+#include "jni/ContextSelectionClient_jni.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF16ToJavaString;
+using base::android::JavaParamRef;
+using base::android::ScopedJavaLocalRef;
+
+namespace content {
+
+namespace {
+const void* const kContextSelectionClientUDKey = &kContextSelectionClientUDKey;
+}
+
+// This class deletes ContextSelectionClient when WebContents is destroyed.
+class ContextSelectionClient::UserData : public base::SupportsUserData::Data {
+ public:
+  explicit UserData(ContextSelectionClient* client) : client_(client) {}
+
+ private:
+  std::unique_ptr<ContextSelectionClient> client_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(UserData);
+};
+
+jlong Init(JNIEnv* env,
+           const JavaParamRef<jobject>& obj,
+           const JavaParamRef<jobject>& jweb_contents) {
+  WebContents* web_contents = WebContents::FromJavaWebContents(jweb_contents);
+  CHECK(web_contents)
+      << "A ContextSelectionClient should be created with a valid WebContents.";
+
+  return reinterpret_cast<intptr_t>(
+      new ContextSelectionClient(env, obj, web_contents));
+}
+
+ContextSelectionClient::ContextSelectionClient(
+    JNIEnv* env,
+    const base::android::JavaRef<jobject>& obj,
+    WebContents* web_contents)
+    : java_ref_(env, obj),
+      web_contents_(web_contents),
+      weak_ptr_factory_(this) {
+  DCHECK(!web_contents_->GetUserData(kContextSelectionClientUDKey));
+  web_contents_->SetUserData(kContextSelectionClientUDKey, new UserData(this));
+}
+
+ContextSelectionClient::~ContextSelectionClient() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
+  java_ref_.reset();
+  if (!j_obj.is_null()) {
+    Java_ContextSelectionClient_onNativeSideDestroyed(
+        env, j_obj, reinterpret_cast<intptr_t>(this));
+  }
+}
+
+void ContextSelectionClient::RequestSurroundingText(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    int callback_data) {
+  RenderFrameHost* focused_frame = web_contents_->GetFocusedFrame();
+  if (!focused_frame) {
+    OnSurroundingTextReceived(callback_data, base::string16(), 0, 0);
+    return;
+  }
+
+  constexpr int EXTRA_CHARS = 100;
+  focused_frame->RequestTextSurroundingSelection(
+      base::Bind(&ContextSelectionClient::OnSurroundingTextReceived,
+                 weak_ptr_factory_.GetWeakPtr(), callback_data),
+      EXTRA_CHARS);
+}
+
+void ContextSelectionClient::CancelAllRequests(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  weak_ptr_factory_.InvalidateWeakPtrs();
+}
+
+void ContextSelectionClient::OnSurroundingTextReceived(
+    int callback_data,
+    const base::string16& text,
+    int start,
+    int end) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
+  if (!obj.is_null()) {
+    ScopedJavaLocalRef<jstring> j_text = ConvertUTF16ToJavaString(env, text);
+    Java_ContextSelectionClient_onSurroundingTextReceived(
+        env, obj, callback_data, j_text, start, end);
+  }
+}
+
+bool RegisterContextSelectionClient(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace content