Add a Content API around TracingController.

content/browser/trace_controller_impl.h

Index: content/browser/trace_controller_impl.h
===================================================================
--- content/browser/trace_controller_impl.h	(revision 126271)
+++ content/browser/trace_controller_impl.h	(working copy)
@@ -2,49 +2,25 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_BROWSER_TRACE_CONTROLLER_H_
-#define CONTENT_BROWSER_TRACE_CONTROLLER_H_
+#ifndef CONTENT_BROWSER_TRACE_CONTROLLER_IMPL_H_
+#define CONTENT_BROWSER_TRACE_CONTROLLER_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/debug/trace_event.h"
-#include "base/memory/ref_counted_memory.h"
 #include "base/memory/singleton.h"
-#include "content/common/content_export.h"
+#include "content/public/browser/trace_controller.h"
 
 class CommandLine;
 class TraceMessageFilter;
 
-// Objects interested in receiving trace data derive from TraceSubscriber.
-// See also: trace_message_filter.h
-// See also: child_trace_message_filter.h
-class CONTENT_EXPORT TraceSubscriber {
- public:
-  // Called once after TraceController::EndTracingAsync.
-  virtual void OnEndTracingComplete() = 0;
-  // Called 0 or more times between TraceController::BeginTracing and
-  // OnEndTracingComplete. Use base::debug::TraceResultBuffer to convert one or
-  // more trace fragments to JSON.
-  virtual void OnTraceDataCollected(
-      const scoped_refptr<base::RefCountedString>& trace_fragment) = 0;
-  // Called once after TraceController::GetKnownCategoriesAsync.
-  virtual void OnKnownCategoriesCollected(
-      const std::set<std::string>& known_categories);
-  virtual void OnTraceBufferPercentFullReply(float percent_full);
+namespace content {
 
- protected:
-  virtual ~TraceSubscriber();
-};
-
-// TraceController is used on the browser processes to enable/disable
-// trace status and collect trace data. Only the browser UI thread is allowed
-// to interact with the TraceController object. All calls on the TraceSubscriber
-// happen on the UI thread.
-class CONTENT_EXPORT TraceController {
+class TraceControllerImpl : public TraceController {
  public:
-  static TraceController* GetInstance();
+  static TraceControllerImpl* GetInstance();
 
   // Called on the main thread of the browser process to initialize
   // startup tracing.
@@ -55,19 +31,6 @@
   // when once the categories are retrieved from child processes.
   bool GetKnownCategoriesAsync(TraceSubscriber* subscriber);
 
-  // Called by browser process to start tracing events on all processes.
-  //
-  // Currently only one subscriber is allowed at a time.
-  // Tracing begins immediately locally, and asynchronously on child processes
-  // as soon as they receive the BeginTracing request.
-  // By default, all categories are traced except those matching "test_*".
-  //
-  // If BeginTracing was already called previously,
-  //   or if an EndTracingAsync is pending,
-  //   or if another subscriber is tracing,
-  //   BeginTracing will return false meaning it failed.
-  bool BeginTracing(TraceSubscriber* subscriber);
-
   // Same as above, but specifies which categories to trace.
   // If both included_categories and excluded_categories are empty,
   //   all categories are traced.
@@ -77,57 +40,23 @@
                     const std::vector<std::string>& included_categories,
                     const std::vector<std::string>& excluded_categories);
 
-  // |categories| is a comma-delimited list of category wildcards.
-  // A category can have an optional '-' prefix to make it an excluded category.
-  // All the same rules apply above, so for example, having both included and
-  // excluded categories in the same list would not be supported.
-  //
-  // Example: BeginTracing("test_MyTest*");
-  // Example: BeginTracing("test_MyTest*,test_OtherStuff");
-  // Example: BeginTracing("-excluded_category1,-excluded_category2");
-  bool BeginTracing(TraceSubscriber* subscriber, const std::string& categories);
+  // TraceController implementation:
+  virtual bool BeginTracing(TraceSubscriber* subscriber) OVERRIDE;
+  virtual bool BeginTracing(TraceSubscriber* subscriber,
+                            const std::string& categories) OVERRIDE;
+  virtual  bool EndTracingAsync(TraceSubscriber* subscriber) OVERRIDE;
+  virtual bool GetTraceBufferPercentFullAsync(
+      TraceSubscriber* subscriber) OVERRIDE;
+  virtual void CancelSubscriber(TraceSubscriber* subscriber) OVERRIDE;
 
-  // Called by browser process to stop tracing events on all processes.
-  //
-  // Child processes typically are caching trace data and only rarely flush
-  // and send trace data back to the browser process. That is because it may be
-  // an expensive operation to send the trace data over IPC, and we would like
-  // to avoid much runtime overhead of tracing. So, to end tracing, we must
-  // asynchronously ask all child processes to flush any pending trace data.
-  //
-  // Once all child processes have acked the EndTracing request,
-  // TraceSubscriber will be called with OnEndTracingComplete.
-  //
-  // If a previous call to EndTracingAsync is already pending,
-  //   or if another subscriber is tracing,
-  //   EndTracingAsync will return false meaning it failed.
-  bool EndTracingAsync(TraceSubscriber* subscriber);
-
-  // Get the maximum across processes of trace buffer percent full state.
-  // When the TraceBufferPercentFull value is determined,
-  // subscriber->OnTraceBufferPercentFullReply is called.
-  // When any child process reaches 100% full, the TraceController will end
-  // tracing, and call TraceSubscriber::OnEndTracingComplete.
-  // GetTraceBufferPercentFullAsync fails in the following conditions:
-  //   trace is ending or disabled;
-  //   a previous call to GetTraceBufferPercentFullAsync is pending; or
-  //   the caller is not the current subscriber.
-  bool GetTraceBufferPercentFullAsync(TraceSubscriber* subscriber);
-
-  // Cancel the subscriber so that it will not be called when EndTracingAsync is
-  // acked by all child processes. This will also call EndTracingAsync
-  // internally if necessary.
-  // Safe to call even if caller is not the current subscriber.
-  void CancelSubscriber(TraceSubscriber* subscriber);
-
  private:
   typedef std::set<scoped_refptr<TraceMessageFilter> > FilterMap;
 
-  friend struct DefaultSingletonTraits<TraceController>;
-  friend class TraceMessageFilter;
+  friend struct DefaultSingletonTraits<TraceControllerImpl>;
+  friend class ::TraceMessageFilter;
 
-  TraceController();
-  ~TraceController();
+  TraceControllerImpl();
+  virtual ~TraceControllerImpl();
 
   bool is_tracing_enabled() const {
     return can_end_tracing();
@@ -173,8 +102,10 @@
   std::vector<std::string> included_categories_;
   std::vector<std::string> excluded_categories_;
 
-  DISALLOW_COPY_AND_ASSIGN(TraceController);
+  DISALLOW_COPY_AND_ASSIGN(TraceControllerImpl);
 };
 
-#endif  // CONTENT_BROWSER_TRACE_CONTROLLER_H_
+}  // namespace content
 
+#endif  // CONTENT_BROWSER_TRACE_CONTROLLER_IMPL_H_
+