Add UMA for testing whether the Chromium library was page aligned in the APK file.

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 c56d76c97d354f0886ad106f0ebdeb5b0d7b0544..93b6eb15f8b0452a8aee37b700a07d71f7b5b190 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
@@ -314,6 +314,10 @@ public class LibraryLoader {
             nativeRecordChromiumAndroidLinkerBrowserHistogram(sIsUsingBrowserSharedRelros,
                                                               sLoadAtFixedAddressFailed,
                                                               getLibraryLoadFromApkStatus(context));
+            if (Linker.isInZipFile()) {
+                nativeRecordChromiumAndroidLinkerLibraryAlignmentInApk(

[picksi1, 2014/10/28 11:37:08]

This reads like you're checking if the linker is in a zip file (?) if this is
your function should it be called isAPKZipped() ... or have I misunderstood its
use?

[petrcermak, 2014/10/28 12:16:48]

I don't like the name either. It returns true iff the Chromium library should be
loaded directly from the APK. I didn't change the name because the whole class
will need a complete refactoring anyway.

+                        getLibraryAlignmentInApk(context));
+            }
         }
     }
 
@@ -336,6 +340,27 @@ public class LibraryLoader {
                 LibraryLoadFromApkStatusCodes.NOT_SUPPORTED;
     }
 
+    // Returns true if the Chromium library is page aligned in the APK file.
+    // This method can only be called when the Chromium linker is used and the library
+    // can be loaded directly from the APK file.
+    private static boolean getLibraryAlignmentInApk(Context context) {
+        assert Linker.isUsed();
+        assert Linker.isInZipFile();
+
+        if (NativeLibraries.LIBRARIES.length != 2) {
+            Log.w(TAG, "NativeLibraryes.LIBRARIES should contain exactly 2 libraries");

[picksi1, 2014/10/28 11:37:08]

Is there a const or enum etc. we can use to avoid using a magic number 2 here?

[petrcermak, 2014/10/28 12:16:48]

I removed this code. The point was that there should be only the Chromium linker
library (which is *not* loaded directly from the APK) and Chromium library
(which *is* loaded directly from the APK).

+        }
+
+        for (String library : NativeLibraries.LIBRARIES) {
+            if (!Linker.isLinkerLibrary(library)) {
+                return Linker.checkLibraryAlignedInApk(context.getApplicationInfo().sourceDir,
+                                                       System.mapLibraryName(library));
+            }
+        }
+
+        return false;
+    }
+
     // Register pending Chromium linker histogram state for renderer processes. This cannot be
     // recorded as a histogram immediately because histograms and IPC are not ready at the
     // time it are captured. This function stores a pending value, so that a later call to
@@ -367,6 +392,11 @@ public class LibraryLoader {
             boolean loadAtFixedAddressFailed,
             int libraryLoadFromApkStatus);
 
+    // Method called to record statistics about the page alignment of the Chromium library
+    // in the APK file.
+    private static native void nativeRecordChromiumAndroidLinkerLibraryAlignmentInApk(
+            boolean aligned);
+
     // Method called to register (for later recording) statistics about the Chromium linker
     // operation for a renderer process. Indicates whether the linker attempted relro sharing,
     // and if it did, whether the library failed to load at a fixed address.