Fix low-memory devices crashing on Chrome start up during UMA recodring

base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java

Index: base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
diff --git a/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java b/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
index 86bca4399d2abf908ebb34f501de147a7e2484b0..6eee0349b9a07d92a1e613c8bc79c4c1bbf958af 100644
--- a/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
+++ b/base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java
@@ -50,9 +50,12 @@ public class LibraryLoader {
     private static boolean sIsUsingBrowserSharedRelros = false;
     private static boolean sLoadAtFixedAddressFailed = false;
 
-    // One-way switch recording whether the device supports memory mapping
-    // APK files with executable permissions. Only used in the browser.
-    private static boolean sLibraryLoadFromApkSupported = false;
+    // The name of the APK file.
+    private static String sApkFileName = null;
+
+    // One-way switch becomes true when the library is successfully loaded from

[rmcilroy, 2014/10/20 10:42:39]

nit - One-way switch becomes true if the library was loaded from the APK
directly.

[petrcermak, 2014/10/20 15:33:22]

Done.

+    // the APK file.
+    private static boolean sLibraryLoadedFromApk = false;

[rmcilroy, 2014/10/20 10:42:39]

nit - sLibraryWasLoadedFromApk

[petrcermak, 2014/10/20 15:33:22]

Done.

 
     // One-way switch becomes true if the system library loading failed,
     // and the right native library was found and loaded by the hack.
@@ -160,21 +163,18 @@ public class LibraryLoader {
                 long startTime = SystemClock.uptimeMillis();
                 boolean useChromiumLinker = Linker.isUsed();
 
+                if (context != null) {
+                    sApkFileName = context.getApplicationInfo().sourceDir;
+                }
+
                 if (useChromiumLinker) {
                     // Load libraries using the Chromium linker.
                     Linker.prepareLibraryLoad();
 
-                    // Check if the device supports loading a library directly from the APK file.
-                    String apkfile = context.getApplicationInfo().sourceDir;
-                    if (Linker.isInBrowserProcess()) {
-                        sLibraryLoadFromApkSupported = Linker.checkLibraryLoadFromApkSupport(
-                                apkfile);
-                    }
-
                     for (String library : NativeLibraries.LIBRARIES) {
                         String zipfile = null;
                         if (Linker.isInZipFile()) {
-                            zipfile = apkfile;
+                            zipfile = sApkFileName;
                             Log.i(TAG, "Loading " + library + " from within " + zipfile);
                         } else {
                             Log.i(TAG, "Loading: " + library);
@@ -186,6 +186,7 @@ public class LibraryLoader {
                             try {
                                 if (zipfile != null) {
                                     Linker.loadLibraryInZipFile(zipfile, library);
+                                    sLibraryLoadedFromApk = true;
                                 } else {
                                     Linker.loadLibrary(library);
                                 }
@@ -200,6 +201,7 @@ public class LibraryLoader {
                         if (!isLoaded) {
                             if (zipfile != null) {
                                 Linker.loadLibraryInZipFile(zipfile, library);
+                                sLibraryLoadedFromApk = true;
                             } else {
                                 Linker.loadLibrary(library);
                             }
@@ -316,10 +318,20 @@ public class LibraryLoader {
     // onNativeInitializationComplete().
     private static void recordBrowserProcessHistogram() {

[rmcilroy, 2014/10/20 10:42:39]

It looks like this is only called from onNativeInitializationComplete(), which
itself is only called from NativeInitializationController, which has a mContext
field.  Could we pass the context to this function in order to avoid storing
sApkFileName as a static field?

[petrcermak, 2014/10/20 15:33:22]

Done.

         if (Linker.isUsed()) {
-            assert Linker.isInBrowserProcess();
+            int libraryLoadFromApkSupport;

[rmcilroy, 2014/10/20 10:42:39]

nit - libraryLoadFromApkStatus

[petrcermak, 2014/10/20 15:33:22]

The variable is not needed now that the code is in a separate function.

+            if (sLibraryLoadedFromApk) {
+                libraryLoadFromApkSupport = LibraryLoadFromApkSupportCode.SUCCESSFUL;
+            } else if (sApkFileName != null) {
+                libraryLoadFromApkSupport = Linker.checkLibraryLoadFromApkSupport(sApkFileName) ?
+                        LibraryLoadFromApkSupportCode.SUPPORTED :
+                        LibraryLoadFromApkSupportCode.NOT_SUPPORTED;
+            } else {
+                libraryLoadFromApkSupport = LibraryLoadFromApkSupportCode.UNKNOWN;
+                Log.w(TAG, "Unknown APK filename due to null context");
+            }

[rmcilroy, 2014/10/20 10:42:39]

Please pull this out into a separate function which returns the
libraryLoadFromApkStatus and just call it on the line below.

[petrcermak, 2014/10/20 15:33:22]

Done.

             nativeRecordChromiumAndroidLinkerBrowserHistogram(sIsUsingBrowserSharedRelros,
                                                               sLoadAtFixedAddressFailed,
-                                                              sLibraryLoadFromApkSupported);
+                                                              libraryLoadFromApkSupport);
         }
     }
 
@@ -348,11 +360,11 @@ public class LibraryLoader {
     // Method called to record statistics about the Chromium linker operation for the main
     // browser process. Indicates whether the linker attempted relro sharing for the browser,
     // and if it did, whether the library failed to load at a fixed address. Also records
-    // support for memory mapping APK files with executable permissions.
+    // support for loading a library directly from the APK file.
     private static native void nativeRecordChromiumAndroidLinkerBrowserHistogram(
             boolean isUsingBrowserSharedRelros,
             boolean loadAtFixedAddressFailed,
-            boolean apkMemoryMappingSupported);
+            int libraryLoadFromApkSupport);
 
     // Method called to register (for later recording) statistics about the Chromium linker
     // operation for a renderer process. Indicates whether the linker attempted relro sharing,