Revert "Fixed compiler warning C4267 'conversion from 'size_t' to 'type', possible loss of data'"

Seems to have quite a few warnings in 64-bit on my machine.

BUG=angleproject:1120

This reverts commit c5cf9bc47d0ee028adbbf9e9f94ca567eec601dc.

Change-Id: I86768b900aeba52e7a2242d9ae8949f93f1a5ba9
Reviewed-on: https://chromium-review.googlesource.com/293280
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Config.cpp b/src/libANGLE/Config.cpp
index c558b31..1b1fc50 100644
--- a/src/libANGLE/Config.cpp
+++ b/src/libANGLE/Config.cpp
@@ -64,7 +64,7 @@
 EGLint ConfigSet::add(const Config &config)
 {
     // Set the config's ID to a small number that starts at 1 ([EGL 1.5] section 3.4)
-    EGLint id = static_cast<EGLint>(mConfigs.size()) + 1;
+    EGLint id = mConfigs.size() + 1;
 
     Config copyConfig(config);
     copyConfig.configID = id;