Move crash keys for command-line switches to components/crash so they can be set

components/crash/core/common/crash_keys.h

Index: components/crash/core/common/crash_keys.h
diff --git a/components/crash/core/common/crash_keys.h b/components/crash/core/common/crash_keys.h
index 70b77ae1165a3ddb3209300e7fc6cf52d8b56dc9..494198aaf066eb103dcb52b0af4c2f06123767bf 100644
--- a/components/crash/core/common/crash_keys.h
+++ b/components/crash/core/common/crash_keys.h
@@ -8,8 +8,13 @@
 #include <string>
 #include <vector>
 
+#include "base/debug/crash_logging.h"
 #include "build/build_config.h"
 
+namespace base {
+class CommandLine;
+}  // namespace base
+
 namespace crash_keys {
 
 // Sets the ID (which may either be a full GUID or a GUID that was already
@@ -21,6 +26,20 @@ void ClearMetricsClientId();
 // Sets the list of active experiment/variations info.
 void SetVariationsList(const std::vector<std::string>& variations);
 
+// Adds a common set of crash keys for holding command-line switches to |keys|.
+void GetCrashKeysForCommandLineSwitches(
+    std::vector<base::debug::CrashKey>* keys);
+
+// A function returning true if |flag| is a switch that should be filtered out
+// of crash keys.
+typedef bool (*SwitchFilterFunction)(const std::string &flag);
+
+// Sets the kNumSwitches key and a set of keys named using kSwitchFormat based
+// on the given |command_line|. If |skip_filter| is not null, ignore any switch
+// for which it returns true.
+void SetSwitchesFromCommandLine(const base::CommandLine& command_line,
+                                SwitchFilterFunction skip_filter = nullptr);

[grt (UTC plus 2), 2015/11/27 21:32:53]

in general, default arguments are banned
(https://google.github.io/styleguide/cppguide.html#Default_Arguments). i think
it's fine to pass nullptr explicitly at the one callsite. if that unappealing to
you, then i think the overload is better. sorry for the back-and-forth.

[Joe Mason, 2015/11/27 22:29:14]

Done.

+
 // Crash Key Constants /////////////////////////////////////////////////////////
 
 // kChunkMaxLength is the platform-specific maximum size that a value in a
@@ -68,6 +87,18 @@ extern const char kNumVariations[];
 // typically set by SetExperimentList.
 extern const char kVariations[];
 
+// The maximum number of command line switches to process. |kSwitchFormat|
+// should be formatted with an integer in the range [1, kSwitchesMaxCount].
+const size_t kSwitchesMaxCount = 15;
+
+// A printf-style format string naming the set of crash keys corresponding to
+// at most |kSwitchesMaxCount| command line switches.
+extern const char kSwitchFormat[];
+
+// The total number of switches, used to report the total in case more than
+// |kSwitchesMaxCount| are present.
+extern const char kNumSwitches[];
+
 // Used to help investigate bug 464926.
 extern const char kBug464926CrashKey[];