SkImageEncoder: simplify API

  - Hide SkImageEncoder class in private header.
  - SkImageEncoder::Type becomes SkEncodedImageFormat
  - SkEncodedFormat becomes SkEncodedImageFormat
  - SkImageEncoder static functions replaced with
    single function EncodeImage()
  - utility wrappers for EncodeImage() are in
    sk_tool_utils.h

TODO: remove link-time registration mechanism.
TODO: clean up clients use of API and flip the flag.
TODO: implement EncodeImage() in chromeium/skia/ext

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4909

Change-Id: Ib48b31fdc05cf23cda7f56ebfd67c841c149ce70
Reviewed-on: https://skia-review.googlesource.com/4909
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/tests/PathOpsConicIntersectionTest.cpp b/tests/PathOpsConicIntersectionTest.cpp
index 41c0acb..1de1583 100644
--- a/tests/PathOpsConicIntersectionTest.cpp
+++ b/tests/PathOpsConicIntersectionTest.cpp
@@ -110,8 +110,8 @@
     canvas.drawPath(path, paint);
     SkString filename("c:\\Users\\caryclark\\Documents\\");
     filename.appendf("%s.png", name);
-    SkImageEncoder::EncodeFile(filename.c_str(), bitmap,
-            SkImageEncoder::kPNG_Type, 100);
+    sk_tool_utils::EncodeImageToFile(filename.c_str(), bitmap,
+            SkEncodedImageFormat::kPNG, 100);
 }
 
 static void writeDPng(const SkDConic& dC, const char* name) {
@@ -152,8 +152,8 @@
     canvas.drawPath(path, paint);
     SkString filename("c:\\Users\\caryclark\\Documents\\");
     filename.appendf("%s.png", name);
-    SkImageEncoder::EncodeFile(filename.c_str(), bitmap,
-            SkImageEncoder::kPNG_Type, 100);
+    sk_tool_utils::EncodeImageToFile(filename.c_str(), bitmap,
+            SkEncodedImageFormat::kPNG, 100);
 }
 #endif
 
@@ -290,7 +290,7 @@
         }
         SkString filename("c:\\Users\\caryclark\\Documents\\");
         filename.appendf("f%d.png", index);
-        SkImageEncoder::EncodeFile(filename.c_str(), bitmap, SkImageEncoder::kPNG_Type, 100);
+        sk_tool_utils::EncodeImageToFile(filename.c_str(), bitmap, SkEncodedImageFormat::kPNG, 100);
     }
 }
 #endif