[Android] spellcheck: add availability UMA.

components/spellcheck/browser/spellchecker_session_bridge_android.cc

 // Copyright 2015 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/spellcheck/browser/spellchecker_session_bridge_android.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
+#include "base/metrics/histogram_macros.h"
 #include "components/spellcheck/common/spellcheck_messages.h"
 #include "components/spellcheck/common/spellcheck_result.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "jni/SpellCheckerSessionBridge_jni.h"
 
 using base::android::JavaParamRef;
 
+namespace {
+
+void RecordAvailabilityUMA(bool spellcheck_available) {
+  UMA_HISTOGRAM_BOOLEAN("Spellcheck.Android.Available", spellcheck_available);
+}
+
+}  // namespace
+
 SpellCheckerSessionBridge::SpellCheckerSessionBridge(int render_process_id)
     : render_process_id_(render_process_id),
-      java_object_initialization_failed_(false) {}
+      java_object_initialization_failed_(false),
+      active_session_(false) {}
 
 SpellCheckerSessionBridge::~SpellCheckerSessionBridge() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // Clean-up java side to avoid any stale JNI callbacks.
   DisconnectSession();
 }
 
 // static
 bool SpellCheckerSessionBridge::RegisterJNI(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 void SpellCheckerSessionBridge::RequestTextCheck(int route_id,
                                                  int identifier,
                                                  const base::string16& text) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   // SpellCheckerSessionBridge#create() will return null if spell checker
   // service is unavailable.
-  if (java_object_initialization_failed_)
+  if (java_object_initialization_failed_) {
+    if (!active_session_) {
+      RecordAvailabilityUMA(false);
+      active_session_ = true;
+    }
     return;
+  }
 
   // RequestTextCheck IPC arrives at the message filter before
   // ToggleSpellCheck IPC when the user focuses an input field that already
   // contains completed text.  We need to initialize the spellchecker here
   // rather than in response to ToggleSpellCheck so that the existing text
   // will be spellchecked immediately.
   if (java_object_.is_null()) {
     java_object_.Reset(Java_SpellCheckerSessionBridge_create(
         base::android::AttachCurrentThread(),
         reinterpret_cast<intptr_t>(this)));
+    if (!active_session_) {
+      RecordAvailabilityUMA(!java_object_.is_null());
+      active_session_ = true;
+    }
     if (java_object_.is_null()) {
       java_object_initialization_failed_ = true;
       return;
     }
   }
 
   // Save incoming requests to run at the end of the currently active request.
   // If multiple requests arrive during one active request, only the most
   // recent request will run (the others get overwritten).
   if (active_request_) {
@@ skipping 44 matching lines @@
   }
 }
 
 void SpellCheckerSessionBridge::DisconnectSession() {
   // Needs to be executed on the same thread as the RequestTextCheck and
   // ProcessSpellCheckResults methods, which is the UI thread.
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   active_request_.reset();
   pending_request_.reset();
+  active_session_ = false;
 
   if (!java_object_.is_null()) {
     Java_SpellCheckerSessionBridge_disconnect(
         base::android::AttachCurrentThread(), java_object_);
     java_object_.Reset();
   }
 }
 
 SpellCheckerSessionBridge::SpellingRequest::SpellingRequest(
     int route_id,
     int identifier,
     const base::string16& text)
     : route_id(route_id), identifier(identifier), text(text) {}
 
 SpellCheckerSessionBridge::SpellingRequest::~SpellingRequest() {}