Fix issue #3108683: GRH18: Battery usage chart FCs

Make array more bigger, and bounds check the thing.

Change-Id: Iaffebefd27c16c6ecf57566803859be1a5049b8a

src/com/android/settings/fuelgauge/BatteryHistoryChart.java

@@ -59,7 +59,7 @@ public class BatteryHistoryChart extends View {
 
         void init(int width) {
             if (width > 0) {
-                mTicks = new int[width+2];
+                mTicks = new int[width*2];
             } else {
                 mTicks = null;
             }
@@ -68,7 +68,7 @@ public class BatteryHistoryChart extends View {
         }
 
         void addTick(int x, int bin) {
-            if (bin != mLastBin) {
+            if (bin != mLastBin && mNumTicks < mTicks.length) {
                 mTicks[mNumTicks] = x | bin << CHART_DATA_BIN_SHIFT;
                 mNumTicks++;
                 mLastBin = bin;