Blobs: Mechanism for creating Blobs in browser process, then transferring to renderer.

content/public/browser/browser_context.h

Index: content/public/browser/browser_context.h
diff --git a/content/public/browser/browser_context.h b/content/public/browser/browser_context.h
index d4e80b218a3e79e4fdc658a959467f3568591d79..bd6e1549c281c2597d409f5397ac48294fac6ec3 100644
--- a/content/public/browser/browser_context.h
+++ b/content/public/browser/browser_context.h
@@ -31,6 +31,7 @@ class SpecialStoragePolicy;
 
 namespace content {
 
+class BlobContext;
 class BrowserPluginGuestManagerDelegate;
 class DownloadManager;
 class DownloadManagerDelegate;
@@ -77,6 +78,9 @@ class CONTENT_EXPORT BrowserContext : public base::SupportsUserData {
   static content::StoragePartition* GetDefaultStoragePartition(
       BrowserContext* browser_context);
 
+  // Returns the BlobContext for this context.
+  static content::BlobContext* GetBlobContext(BrowserContext* browser_context);

[jam, 2014/05/12 22:35:03]

why expose this "blob context" concept to embedders? all you need is one method
on this class. same for BlobHandle, just use string

[tommycli, 2014/05/12 23:35:05]

BlobHandle's content-private implementing class (See
chrome_blob_storage_context.cc) holds a reference to the underlying
BlobDataHandle and thus controls its lifetime. I've updated the comments to
BlobHandle.

As to why BlobContext is a separate class? See
https://codereview.chromium.org/250143002/ comments for discussion leading to
current design.

I suspect we didn't want to put add a CreateMemoryBackedBlob method in every
class that implements the BrowserContext interface. And - we might add more Blob
methods in the future.

[jam, 2014/05/13 02:44:23]

ah, I missed that sorry. ok please put this in a separate file per
http://www.chromium.org/developers/content-module/content-api. also get rid of
the DISALLOW_COPY_AND_ASSIGN as an abstract class can't be copied.
I haven't read through all the comments in that link; but I don't understand
your sentence above. how is a static method that returns a class which has a
method foo different from having foo be a static method directly? the one
implementation would still be in content

[tommycli, 2014/05/13 18:27:42]

Done.

+
   // Ensures that the corresponding ResourceContext is initialized. Normally the
   // BrowserContext initializs the corresponding getters when its objects are
   // created, but if the embedder wants to pass the ResourceContext to another