Set active extension IDs for crash reports using the crash key logging system.

chrome/common/crash_keys.h

Index: chrome/common/crash_keys.h
diff --git a/chrome/common/crash_keys.h b/chrome/common/crash_keys.h
index 45bb6779e935d38e8f5178d2a57de64806c83fe4..0054011fb818143f63e5c9798eb7c2a30013c82b 100644
--- a/chrome/common/crash_keys.h
+++ b/chrome/common/crash_keys.h
@@ -5,6 +5,9 @@
 #ifndef CHROME_COMMON_CRASH_KEYS_H_
 #define CHROME_COMMON_CRASH_KEYS_H_
 
+#include <set>
+#include <string>
+
 #include "base/debug/crash_logging.h"
 
 namespace crash_keys {
@@ -13,11 +16,28 @@ namespace crash_keys {
 // reporting server. Returns the size of the union of all keys.
 size_t RegisterChromeCrashKeys();
 
+// Sets the list of "active" extensions in this process. We overload "active" to
+// mean different things depending on the process type:
+// - browser: all enabled extensions
+// - renderer: the unique set of extension ids from all content scripts
+// - extension: the id of each extension running in this process (there can be
+//   multiple because of process collapsing).
+void SetActiveExtensions(const std::set<std::string>& extensions);
+
 // Crash Key Name Constants ////////////////////////////////////////////////////
 
 // The URL of the active tab.
 extern const char kActiveURL[];
 
+// Installed extensions. |kExtensionID| should be formatted with an integer,
+// in the range [0, kExtensionIDMaxCount).
+const size_t kExtensionIDMaxCount = 10;
+extern const char kExtensionID[];
+// The total number of installed extensions, recorded in case it exceeds
+// kExtensionIDMaxCount. Also used in chrome/app, but defined here to avoid
+// a common->app dependency.
+extern const char kNumExtensionsCount[];
+
 // GPU information.
 #if !defined(OS_ANDROID)
 extern const char kGPUVendorID[];