[WebSocket] Add comment about the flag values.

Added why the value is not a power of 2.

Change-Id: I987c50197d8535b2020e9576bdefe3c3ba71c1e0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1792509
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Auto-Submit: Yoichi Osato <yoichio@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695036}

net/websockets/websocket_basic_stream.cc

@@ -74,6 +74,7 @@ const uint64_t kMaxControlFramePayload = 125;
 #if defined(OS_ANDROID)
 const int kReadBufferSize = 32 * 1024;
 #else
+// |2^n - delta| is better than 2^n on Linux. See crrev.com/c/1792208.
 const int kReadBufferSize = 131000;
 #endif
 

net/websockets/websocket_channel.h

@@ -156,6 +156,7 @@ class NET_EXPORT WebSocketChannel {
 #if defined(OS_ANDROID)
   static const uint64_t kReceiveQuotaThreshold = 1 << 15;
 #else
+  // |2^n - delta| is better than 2^n on Linux. See crrev.com/c/1792208.
   static const uint64_t kReceiveQuotaThreshold = 65500;
 #endif