Adding support for sampling crashes in Chrome on Windows.

components/crash/content/app/crash_reporter_client.h

Index: components/crash/content/app/crash_reporter_client.h
diff --git a/components/crash/content/app/crash_reporter_client.h b/components/crash/content/app/crash_reporter_client.h
index 157ba53e1361493bcc4632caafa01b0052d8c4ea..392775970115c5a6adc6a0bda7c51c145a6c07ed 100644
--- a/components/crash/content/app/crash_reporter_client.h
+++ b/components/crash/content/app/crash_reporter_client.h
@@ -138,6 +138,11 @@ class CrashReporterClient {
   // 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.