Use stricter type checking in UMA_HISTOGRAM_ENUMERATION

base/android/library_loader/library_loader_hooks.cc

Index: base/android/library_loader/library_loader_hooks.cc
diff --git a/base/android/library_loader/library_loader_hooks.cc b/base/android/library_loader/library_loader_hooks.cc
index 1fe8048a162808a7863574cfd4fc14a687f6c07f..e02c66b2aad3be86bbd34822466b4e31e7fb17a2 100644
--- a/base/android/library_loader/library_loader_hooks.cc
+++ b/base/android/library_loader/library_loader_hooks.cc
@@ -124,9 +124,10 @@ static void RecordChromiumAndroidLinkerBrowserHistogram(
                             MAX_BROWSER_HISTOGRAM_CODE);
 
   // Record the device support for loading a library directly from the APK file.
-  UMA_HISTOGRAM_ENUMERATION("ChromiumAndroidLinker.LibraryLoadFromApkStatus",
-                            library_load_from_apk_status,
-                            LIBRARY_LOAD_FROM_APK_STATUS_CODES_MAX);
+  UMA_HISTOGRAM_ENUMERATION(
+      "ChromiumAndroidLinker.LibraryLoadFromApkStatus",
+      static_cast<LibraryLoadFromApkStatusCodes>(library_load_from_apk_status),
+      LIBRARY_LOAD_FROM_APK_STATUS_CODES_MAX);

[dcheng, 2017/07/17 09:13:59]

Hmm a little sad. I would personally if we did the static cast closer to the
point where we got it back from Java, but that's just a nit

[wychen, 2017/07/17 22:43:09]

This function is the immediate JNI function, and this variable is only used
here. Does it look better this way?

  LibraryLoadFromApkStatusCodes library_load_from_apk_status_code =
      library_load_from_apk_status;

  UMA_HISTOGRAM_ENUMERATION(
      "ChromiumAndroidLinker.LibraryLoadFromApkStatus",
      library_load_from_apk_status_code,
      LIBRARY_LOAD_FROM_APK_STATUS_CODES_MAX);

[dcheng, 2017/07/18 10:28:07]

Ah... I thought this was called as a helper. I didn't realize that JNI would
work for functions with internal linkage. I guess the existing code is fine =)

[wychen, 2017/07/18 21:43:41]

Got it. Let's move on to the split CLs then.

 
   // Record how long it took to load the shared libraries.
   UMA_HISTOGRAM_TIMES("ChromiumAndroidLinker.BrowserLoadTime",