Revert of media: Simplify CdmHostFile(s)

content/common/media/cdm_host_file.cc

Index: content/common/media/cdm_host_file.cc
diff --git a/content/common/media/cdm_host_file.cc b/content/common/media/cdm_host_file.cc
index ff023839ceac545d1a65f4dbdb129fd90923cfb8..99d5cca24a87bf106b481d4f6e288652e80f7dfc 100644
--- a/content/common/media/cdm_host_file.cc
+++ b/content/common/media/cdm_host_file.cc
@@ -10,25 +10,41 @@
 #include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "media/base/media_switches.h"
 #include "media/cdm/api/content_decryption_module_ext.h"
 
 namespace content {
+
+namespace {
+
+bool IgnoreMissingCdmHostFile() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kIgnoreMissingCdmHostFile);
+}
+
+}  // namespace
 
 // static
 std::unique_ptr<CdmHostFile> CdmHostFile::Create(
     const base::FilePath& file_path,
     const base::FilePath& sig_file_path) {
-  DVLOG(1) << __func__;
-
   // Open file at |file_path|.
   base::File file(file_path, base::File::FLAG_OPEN | base::File::FLAG_READ);
-  DVLOG(1) << "  " << file.IsValid() << ": " << file_path.MaybeAsASCII();
+  if (!file.IsValid()) {
+    DVLOG(1) << "Failed to open file at " << file_path.MaybeAsASCII();
+    return nullptr;
+  }
 
   // Also open the sig file at |sig_file_path|.
   base::File sig_file(sig_file_path,
                       base::File::FLAG_OPEN | base::File::FLAG_READ);
-  DVLOG(1) << "  " << sig_file.IsValid() << ": "
-           << sig_file_path.MaybeAsASCII();
+  if (!sig_file.IsValid()) {
+    DVLOG(1) << "Failed to open sig file at " << sig_file_path.MaybeAsASCII();
+    if (!IgnoreMissingCdmHostFile())
+      return nullptr;
+
+    DVLOG(1) << "Ignoring sig file failure at " << sig_file_path.MaybeAsASCII();
+  }
 
   return std::unique_ptr<CdmHostFile>(
       new CdmHostFile(file_path, std::move(file), std::move(sig_file)));
@@ -45,7 +61,12 @@
     : file_path_(file_path),
       file_(std::move(file)),
       sig_file_(std::move(sig_file)) {
-  DCHECK(!file_path_.empty());
+  DVLOG(1) << __func__ << ": " << file_path_.value();
+  DCHECK(!file_path_.empty()) << "File path is empty.";
+  DCHECK(file_.IsValid()) << "Invalid file.";
+
+  if (!IgnoreMissingCdmHostFile())
+    DCHECK(sig_file_.IsValid()) << "Invalid signature file.";
 }
 
 }  // namespace content