Add WebView-specific whitelist for crash keys.

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 513727c08f3f434365e4df6d12ec8bf482104b95..7f6f878af56cc7fcf4281a4812e10b315806541a 100644
--- a/components/crash/content/app/crash_reporter_client.h
+++ b/components/crash/content/app/crash_reporter_client.h
@@ -8,6 +8,7 @@
 #include <stddef.h>
 
 #include <string>
+#include <vector>
 
 #include "base/strings/string16.h"
 #include "build/build_config.h"
@@ -144,6 +145,10 @@ class CrashReporterClient {
   // reporting server. Returns the size of the union of all keys.
   virtual size_t RegisterCrashKeys();
 
+  virtual bool UseCrashKeysWhiteList();
+
+  virtual std::vector<const char*> GetWhiteListedCrashKeys();

[Tobias Sargeant, 2017/02/28 22:18:55]

Because the whitelist is not accessed in a compromised context (only when
setting the crash key value), WDYT about having only:

virtual void GetWhiteListedCrashKeys(std::unordererd_set<std::string>*
whitelist);

I don't think separate Use* and Get* methods are really needed. The default
implementation can just not add any whitelisted keys.

[gsennton, 2017/03/01 15:53:02]

If there aren't any whitelisted keys, shouldn't that mean that you don't want
any keys to be uploaded? :)

+
   // Returns true if running in unattended mode (for automated testing).
   virtual bool IsRunningUnattended();