Revert "Don't keep "outResultsFile" open in nanobench"

This reverts commit 2e1381ec86.

Reason for revert: This causes corrupted JSON output from
                   nanobench

Bug: skia:12078

Original change's description:
> Don't keep "outResultsFile" open in nanobench
>
> There is a bug on Pixel and Pixel2 devices where the program
> eventually terminates with a non-zero exit code. Closing the
> outResultsFile between JSON flushes seems to fix it (for whatever
> reason).
>
> Bug: b/143074513
> Change-Id: I935e982e88758fda19292129c8031f8501cca615
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249821
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Chris Dalton <csmartdalton@google.com>

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: b/143074513
Change-Id: Iad8e4423acbc520f49365859020776110087dacc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/419842
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Herb Derby <herb@google.com>

bench/ResultsWriter.h

@@ -12,7 +12,6 @@
 
 #include "include/core/SkString.h"
 #include "include/core/SkTypes.h"
-#include "src/core/SkOSFile.h"
 #include "src/utils/SkJSONWriter.h"
 #include <cmath>
 
@@ -56,60 +55,4 @@ public:
     }
 };
 
-/**
- NanoFILEAppendAndCloseStream: re-open the file, append the data, then close on every write() call.
-
- The purpose of this class is to not keep the file handle open between JSON flushes. SkJSONWriter
- uses a 32k in-memory cache already, so it only flushes occasionally and is well equipped for a
- steam like this.
-
- See: https://b.corp.google.com/issues/143074513
-*/
-class NanoFILEAppendAndCloseStream : public SkWStream {
-public:
-    NanoFILEAppendAndCloseStream(const char* filePath) : fFilePath(filePath) {
-        // Open the file as "write" to ensure it exists and clear any contents before we begin
-        // appending.
-        FILE* file = sk_fopen(fFilePath.c_str(), kWrite_SkFILE_Flag);
-        if (!file) {
-            SkDebugf("Failed to open file %s for write.\n", fFilePath.c_str());
-            fFilePath.reset();
-            return;
-        }
-        sk_fclose(file);
-    }
-
-    size_t bytesWritten() const override { return fBytesWritten; }
-
-    bool write(const void* buffer, size_t size) override {
-        if (fFilePath.isEmpty()) {
-            return false;
-        }
-
-        FILE* file = sk_fopen(fFilePath.c_str(), kAppend_SkFILE_Flag);
-        if (!file) {
-            SkDebugf("Failed to open file %s for append.\n", fFilePath.c_str());
-            return false;
-        }
-
-        size_t bytesWritten = sk_fwrite(buffer, size, file);
-        fBytesWritten += bytesWritten;
-        sk_fclose(file);
-
-        if (bytesWritten != size) {
-            SkDebugf("NanoFILEAppendAndCloseStream failed writing %d bytes (wrote %d instead)\n",
-                     size, bytesWritten);
-            return false;
-        }
-
-        return true;
-    }
-
-    void flush() override {}
-
-private:
-    SkString fFilePath;
-    size_t fBytesWritten = 0;
-};
-
 #endif

bench/nanobench.cpp

@@ -1228,9 +1228,7 @@ int main(int argc, char** argv) {
     std::unique_ptr<SkWStream> logStream(new SkNullWStream);
     if (!FLAGS_outResultsFile.isEmpty()) {
 #if defined(SK_RELEASE)
-        // SkJSONWriter uses a 32k in-memory cache, so it only flushes occasionally and is well
+        logStream.reset(new SkFILEWStream(FLAGS_outResultsFile[0]));
-        // equipped for a stream that re-opens, appends, and closes the file on every write.
-        logStream.reset(new NanoFILEAppendAndCloseStream(FLAGS_outResultsFile[0]));
 #else
         SkDebugf("I'm ignoring --outResultsFile because this is a Debug build.");
         return 1;

src/core/SkOSFile.h

@@ -17,9 +17,8 @@
 #include "include/private/SkTemplates.h"
 
 enum SkFILE_Flags {
-    kRead_SkFILE_Flag    = 0x01,
+    kRead_SkFILE_Flag   = 0x01,
-    kWrite_SkFILE_Flag   = 0x02,
+    kWrite_SkFILE_Flag  = 0x02
-    kAppend_SkFILE_Flag  = 0x04
 };
 
 FILE* sk_fopen(const char path[], SkFILE_Flags);

src/ports/SkOSFile_stdio.cpp

@@ -72,10 +72,7 @@ FILE* sk_fopen(const char path[], SkFILE_Flags flags) {
         *p++ = 'r';
     }
     if (flags & kWrite_SkFILE_Flag) {
-        SkASSERT(!(flags & kAppend_SkFILE_Flag));
         *p++ = 'w';
-    } else if (flags & kAppend_SkFILE_Flag) {
-        *p++ = 'a';
     }
     *p = 'b';