Photo Picker Dialog: Use sandboxed utility process for decoding images.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/BitmapUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/photo_picker/BitmapUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/BitmapUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/BitmapUtils.java
new file mode 100644
index 0000000000000000000000000000000000000000..ddad8aa24789fdb7444e6fd352f9feaf99e4ae08
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/BitmapUtils.java
@@ -0,0 +1,110 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.photo_picker;
+
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+
+import java.io.FileDescriptor;
+
+/**
+ * A collection of utility functions for dealing with bitmaps.
+ */
+class BitmapUtils {
+    /**
+     * Takes a |bitmap| and returns a square thumbnail of |size|x|size| from the center of the
+     * bitmap specified.
+     * @param bitmap The bitmap to adjust.
+     * @param size The desired size (width and height).
+     * @return The new bitmap thumbnail.
+     */
+    private static Bitmap sizeBitmap(Bitmap bitmap, int size) {
+        // TODO(finnur): Investigate options that require fewer bitmaps to be created.
+        bitmap = ensureMinSize(bitmap, size);
+        bitmap = cropToSquare(bitmap, size);
+        return bitmap;
+    }
+
+    /**
+     * Given a FileDescriptor, decodes the contents and returns a bitmap of
+     * dimensions |size|x|size|.
+     * @param descriptor The FileDescriptor for the file to read.
+     * @param size The width and height of the bitmap to return.
+     * @return The resulting bitmap.
+     */
+    public static Bitmap decodeBitmapFromFileDescriptor(FileDescriptor descriptor, int size) {
+        BitmapFactory.Options options = new BitmapFactory.Options();
+        options.inJustDecodeBounds = true;
+        BitmapFactory.decodeFileDescriptor(descriptor, null, options);
+        options.inSampleSize = calculateInSampleSize(options.outWidth, options.outHeight, size);
+        options.inJustDecodeBounds = false;
+        Bitmap bitmap = BitmapFactory.decodeFileDescriptor(descriptor, null, options);
+
+        if (bitmap == null) return null;
+
+        return sizeBitmap(bitmap, size);
+    }
+
+    /**
+     * Calculates the sub-sampling factor {@link BitmapFactory#inSampleSize} option for a given
+     * image dimensions, which will be used to create a bitmap of a pre-determined size (as small as
+     * possible without either dimension shrinking below |minSize|.
+     * @param width The calculated width of the image to decode.
+     * @param height The calculated height of the image to decode.
+     * @param minSize The maximum size the image should be (in either dimension).
+     * @return The sub-sampling factor (power of two: 1 = no change, 2 = half-size, etc).
+     */
+    private static int calculateInSampleSize(int width, int height, int minSize) {
+        int inSampleSize = 1;
+        if (width > minSize && height > minSize) {
+            inSampleSize = Math.min(width, height) / minSize;
+        }
+        return inSampleSize;
+    }
+
+    /**
+     * Ensures a |bitmap| is at least |size| in both width and height.
+     * @param bitmap The bitmap to modify.
+     * @param size The minimum size (width and height).
+     * @return The resulting (scaled) bitmap.
+     */
+    private static Bitmap ensureMinSize(Bitmap bitmap, int size) {
+        int width = bitmap.getWidth();
+        int height = bitmap.getHeight();
+        if (width >= size && height >= size) return bitmap;
+
+        if (width < size) {
+            float scale = (float) size / width;
+            width = size;
+            height *= scale;
+        }
+
+        if (height < size) {
+            float scale = (float) size / height;
+            height = size;
+            width *= scale;
+        }
+
+        return Bitmap.createScaledBitmap(bitmap, width, height, true);
+    }
+
+    /**
+     * Crops a |bitmap| to a certain square |size|
+     * @param bitmap The bitmap to crop.
+     * @param size The size desired (width and height).
+     * @return The resulting (square) bitmap.
+     */
+    private static Bitmap cropToSquare(Bitmap bitmap, int size) {
+        int x = 0;
+        int y = 0;
+        int width = bitmap.getWidth();
+        int height = bitmap.getHeight();
+        if (width == size && height == size) return bitmap;
+
+        if (width > size) x = (width - size) / 2;
+        if (height > size) y = (height - size) / 2;
+        return Bitmap.createBitmap(bitmap, x, y, size, size);
+    }
+}