Increase heap size during build.

R=ricow

Change-Id: I7662ce930b0ed6d025c58cbb36ebdcb034428c33
diff --git a/build.gradle b/build.gradle
index 35b4c7e..15d8deb 100644
--- a/build.gradle
+++ b/build.gradle
@@ -520,7 +520,7 @@
         // Increase the stack size for the javac process.
         options.forkOptions.jvmArgs << "-Xss256m"
         // Test compilation is sometimes hitting the default limit at 1g, increase it.
-        options.forkOptions.jvmArgs << "-Xmx2g"
+        options.forkOptions.jvmArgs << "-Xmx3g"
         // Set the bootclass path so compilation is consistent with 1.8 target compatibility.
         options.forkOptions.jvmArgs << "-Xbootclasspath/a:third_party/openjdk/openjdk-rt-1.8/rt.jar"
     }