Revert of Hide SkCanvas::LayerIter (patchset #2 id:20001 of https://codereview.chromium.org/1897863008/ )

Reason for revert:
Das roll ist gebusted: https://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_ng/builds/214775/steps/compile%20%28with%20patch%29/logs/stdio

FAILED: /b/build/slave/cache/cipd/goma/gomacc ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/third_party/WebKit/Source/platform/graphics/paint/blink_platform_unittests.PaintArtifactToSkCanvasTest.o.d -DV8_DEPRECATION_WARNINGS -DCLD_VERSION=2 -D__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORE=0 -DCHROMIUM_BUILD -DCR_CLANG_REVISION=266460-1 -DUSE_LIBJPEG_TURBO=1 -DENABLE_WEBRTC=1 -DENABLE_MEDIA_ROUTER=1 -DUSE_PROPRIETARY_CODECS -DENABLE_PEPPER_CDMS -DENABLE_NOTIFICATIONS -DENABLE_TOPCHROME_MD=1 -DDCHECK_ALWAYS_ON=1 -DFIELDTRIAL_TESTING_ENABLED -DENABLE_TASK_MANAGER=1 -DENABLE_EXTENSIONS=1 -DENABLE_PDF=1 -DENABLE_PLUGIN_INSTALLATION=1 -DENABLE_PLUGINS=1 -DENABLE_SESSION_SERVICE=1 -DENABLE_THEMES=1 -DENABLE_AUTOFILL_DIALOG=1 -DENABLE_PRINTING=1 -DENABLE_BASIC_PRINTING=1 -DENABLE_PRINT_PREVIEW=1 -DENABLE_SPELLCHECK=1 -DUSE_BROWSER_SPELLCHECKER=1 -DENABLE_CAPTIVE_PORTAL_DETECTION=1 -DENABLE_APP_LIST=1 -DENABLE_SETTINGS_APP=1 -DENABLE_SUPERVISED_USERS=1 -DENABLE_SERVICE_DISCOVERY=1 -DV8_USE_EXTERNAL_STARTUP_DATA -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DINSIDE_BLINK -DMOJO_USE_SYSTEM_IMPL -DGTEST_HAS_POSIX_RE=0 -DGTEST_LANG_CXX11=0 -DUNIT_TEST -DGTEST_HAS_RTTI=0 -DENABLE_LAYOUT_UNIT_IN_INLINE_BOXES=0 -DENABLE_OILPAN=1 -DWTF_USE_CONCATENATED_IMPULSE_RESPONSES=1 -DENABLE_INPUT_MULTIPLE_FIELDS_UI=1 -DWTF_USE_ICCJPEG=1 -DWTF_USE_QCMSLIB=1 -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_NOEXCEPT= -DU_STATIC_IMPLEMENTATION -DSK_SUPPORT_GPU=1 -DSK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS -DCHROME_PNG_WRITE_SUPPORT -DPNG_USER_CONFIG -DUSE_LIBPCI=1 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -D_FORTIFY_SOURCE=2 -Igen -Igen/blink -I../.. -I../../skia/config -I../../third_party/WebKit/Source -I../../third_party/khronos -I../../gpu -Igen/angle -I../../third_party/WebKit -Igen/third_party/WebKit -I../../testing/gmock/include -I../../testing/gtest/include -I../../third_party/icu/source/i18n -I../../third_party/icu/source/common -I../../third_party/skia/include/core -I../../third_party/skia/include/effects -I../../third_party/skia/include/pdf -I../../third_party/skia/include/gpu -I../../third_party/skia/include/lazy -I../../third_party/skia/include/pathops -I../../third_party/skia/include/pipe -I../../third_party/skia/include/ports -I../../third_party/skia/include/utils -I../../third_party/skia/include/utils/mac -I../../skia/ext -I../../third_party/harfbuzz-ng/src -I../../third_party/qcms/src -I../../third_party/libpng -I../../third_party/zlib -I../../third_party/libwebp -I../../third_party/ots/include -I../../v8/include -I../../third_party/iccjpeg -I../../third_party/libjpeg_turbo -isysroot /Applications/Xcode5.1.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk -O2 -fvisibility=hidden -Werror -mmacosx-version-min=10.7 -arch x86_64 -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wno-selector-type-mismatch -Wpartial-availability -Wheader-hygiene -Wno-char-subscripts -Wno-unneeded-internal-declaration -Wno-covered-switch-default -Wstring-conversion -Wno-c++11-narrowing -Wno-deprecated-register -Wno-inconsistent-missing-override -Wno-shift-negative-value -std=c++11 -stdlib=libc++ -fno-rtti -fno-exceptions -fvisibility-inlines-hidden -fno-threadsafe-statics -Xclang -load -Xclang /b/build/slave/mac/build/src/third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib -Xclang -add-plugin -Xclang find-bad-constructs -Xclang -plugin-arg-find-bad-constructs -Xclang check-templates -Xclang -plugin-arg-find-bad-constructs -Xclang follow-macro-expansion -Xclang -plugin-arg-find-bad-constructs -Xclang check-implicit-copy-ctors -fcolor-diagnostics -fno-strict-aliasing -Xclang -load -Xclang /b/build/slave/mac/build/src/third_party/llvm-build/Release+Asserts/lib/libBlinkGCPlugin.dylib -Xclang -add-plugin -Xclang blink-gc-plugin -Xclang -plugin-arg-blink-gc-plugin -Xclang enable-oilpan -Xclang -plugin-arg-blink-gc-plugin -Xclang warn-raw-ptr  -c ../../third_party/WebKit/Source/platform/graphics/paint/PaintArtifactToSkCanvasTest.cpp -o obj/third_party/WebKit/Source/platform/graphics/paint/blink_platform_unittests.PaintArtifactToSkCanvasTest.o
../../third_party/WebKit/Source/platform/graphics/paint/PaintArtifactToSkCanvasTest.cpp:201:22: error: 'LayerIter' is a protected member of 'SkCanvas'
    return SkCanvas::LayerIter(canvas, false).clip();
                     ^
../../third_party/skia/include/core/SkCanvas.h:1230:18: note: declared protected here
    class SK_API LayerIter /*: SkNoncopyable*/ {
                 ^
1 error generated.
ninja: build stopped: subcommand failed.

Original issue's description:
> Hide SkCanvas::LayerIter
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1897863008
>
> Committed: https://skia.googlesource.com/skia/+/a814000cbb0e90624a410b4359fff7f3ec66f0e0

TBR=reed@google.com,robertphillips@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1906573003
4 files changed