Clean up LappedTransform and Blocker.

- Remove unnecessary window member from lapped_transform.
  - Add comment indicated that Blocker does not take ownership of
    the window passed to its constructor.
  - Streamline LappedTransform constructor so members can be const.

Also use a range-based for loop in audio_processing_impl.cc for clarity.

R=aluebs@webrtc.org, andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/41229004

Cr-Commit-Position: refs/heads/master@{#8708}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8708 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/common_audio/channel_buffer.h

@@ -42,14 +42,13 @@ class ChannelBuffer {
   ChannelBuffer(int num_frames,
                 int num_channels,
                 int num_bands = 1)
-      : data_(new T[num_frames * num_channels]),
+      : data_(new T[num_frames * num_channels]()),
         channels_(new T*[num_channels * num_bands]),
         bands_(new T*[num_channels * num_bands]),
         num_frames_(num_frames),
         num_frames_per_band_(num_frames / num_bands),
         num_channels_(num_channels),
         num_bands_(num_bands) {
-    memset(data_.get(), 0, size() * sizeof(T));
     for (int i = 0; i < num_channels_; ++i) {
       for (int j = 0; j < num_bands_; ++j) {
         channels_[j * num_channels_ + i] =