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..dfa4b27ef74d6d12b6ec40ab40b7a097daa24a9c 100644
--- a/components/crash/core/common/crash_keys.h
+++ b/components/crash/core/common/crash_keys.h
@@ -8,8 +8,14 @@
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
+#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 +27,18 @@ 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);
+
+// Sets the kSwitch and kNumSwitches keys based on the given |command_line|.
+void SetSwitchesFromCommandLine(const base::CommandLine& command_line);

[grt (UTC plus 2), 2015/11/27 18:51:21]

rather than overloading the function, i think it's better to have callers pass
in either an empty callback or a null function pointer (my preference).

[Joe Mason, 2015/11/27 21:16:47]

Done.

+
+// Sets the kSwitch and kNumSwitches keys based on the given |command_line|.
+// Ignore any switch for which |skip_filter| returns true.
+void SetSwitchesFromCommandLine(const base::CommandLine& command_line,
+    const base::Callback<bool(const std::string &)>& skip_filter);

[grt (UTC plus 2), 2015/11/27 18:51:21]

callback seems like overkill. how about starting with a simple function pointer
for now? this can be expanded to a callback in the future if needed.

[Joe Mason, 2015/11/27 21:16:47]

Done.

+
 // Crash Key Constants /////////////////////////////////////////////////////////
 
 // kChunkMaxLength is the platform-specific maximum size that a value in a
@@ -68,6 +86,14 @@ extern const char kNumVariations[];
 // typically set by SetExperimentList.
 extern const char kVariations[];
 
+// Process command line switches. |kSwitch| should be formatted with an integer,
+// in the range [1, kSwitchesMaxCount].
+const size_t kSwitchesMaxCount = 15;
+extern const char kSwitch[];

[grt (UTC plus 2), 2015/11/27 18:51:21]

may as well document this for what it is:
// A printf-style format string naming the set of crash keys corresponding to at
most |kSwitchesMaxCount| command line switches.

i wouldn't object to you renaming this to kSwitchFormat or something like that
since it's a format string rather than an actual crash key name.

[Joe Mason, 2015/11/27 21:16:47]

Done.

+// The total number of switches, used to report the total in case more than

[grt (UTC plus 2), 2015/11/27 18:51:21]

nit: blank line before comment

[Joe Mason, 2015/11/27 21:16:47]

Done.

+// |kSwitchesMaxCount| are present.
+extern const char kNumSwitches[];
+
 // Used to help investigate bug 464926.
 extern const char kBug464926CrashKey[];