Adding support for sampling crashes in Chrome on Windows.

components/crash/content/app/crash_reporter_client.h

 // Copyright 2013 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.
 
 #ifndef COMPONENTS_CRASH_CONTENT_APP_CRASH_REPORTER_CLIENT_H_
 #define COMPONENTS_CRASH_CONTENT_APP_CRASH_REPORTER_CLIENT_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 120 matching lines @@
   // Register all of the potential crash keys that can be sent to the crash
   // reporting server. Returns the size of the union of all keys.
   virtual size_t RegisterCrashKeys();
 
   // Returns true if running in unattended mode (for automated testing).
   virtual bool IsRunningUnattended();
 
   // Returns true if the user has given consent to collect stats.
   virtual bool GetCollectStatsConsent();
 
+  // Returns true if the client is currently in the chosen sample that will
+  // report stats and crashes. Crashes should only be reported if this function
+  // returns true and GetCollectStatsConsent returns true.
+  virtual bool GetCollectStatsInSample();

[robertshield, 2016/08/12 17:49:25]

It seems weird to me that consumers need to know about implementation details to
figure out whether to upload crashes or not. 

I'm guessing that anywhere this is used, callers will have to call
GetCollectStatsConsent() && GetCollectStatsInSample() to determine whether to
upload crashes? That seems like odd leakage.

[jwd, 2016/08/16 19:29:11]

Callers of this from outside crash_reporter shouldn't be making the full
decision of whether to upload. I'm going to have a larger reply with some
details.

I could also make this method private in the chrome implementation.

+
 #if defined(OS_WIN) || defined(OS_MACOSX)
   // Returns true if crash reporting is enforced via management policies. In
   // that case, |breakpad_enabled| is set to the value enforced by policies.
   virtual bool ReportingIsEnforcedByPolicy(bool* breakpad_enabled);
 #endif
 
 #if defined(OS_ANDROID)
   // Returns the descriptor key of the android minidump global descriptor.
   virtual int GetAndroidMinidumpDescriptor();
 
   // Returns true if breakpad microdumps should be enabled. This orthogonal to
   // the standard minidump uploader (which depends on the user consent).
   virtual bool ShouldEnableBreakpadMicrodumps();
 #endif
 
   // Returns true if breakpad should run in the given process type.
   virtual bool EnableBreakpadForProcess(const std::string& process_type);
 };
 
 }  // namespace crash_reporter
 
 #endif  // COMPONENTS_CRASH_CONTENT_APP_CRASH_REPORTER_CLIENT_H_