[quality] There are two identical InMemoryTextResource implementations

[kittaakos]

Bug Description:

https://github.com/eclipse-theia/theia/blob/master/packages/search-in-workspace/src/browser/in-memory-text-resource.ts
https://github.com/eclipse-theia/theia/blob/master/packages/bulk-edit/src/browser/bulk-edit-tree/in-memory-text-resource.ts

Steps to Reproduce:

Additional Information

• Operating System:
• Theia Version:

[kittaakos]

Here is one more:

theia/packages/core/src/common/resource.ts

Lines 255 to 292 in 52d460f

	@injectable()
	export class InMemoryResources implements ResourceResolver {
	protected readonly resources = new SyncReferenceCollection<string, MutableResource>(uri => new MutableResource(new URI(uri)));
	add(uri: URI, contents: string): Resource {
	const resourceUri = uri.toString();
	if (this.resources.has(resourceUri)) {
	throw new Error(`Cannot add already existing in-memory resource '${resourceUri}'`);
	}
	const resource = this.acquire(resourceUri);
	resource.saveContents(contents);
	return resource;
	}
	update(uri: URI, contents: string): Resource {
	const resourceUri = uri.toString();
	const resource = this.resources.get(resourceUri);
	if (!resource) {
	throw new Error(`Cannot update non-existed in-memory resource '${resourceUri}'`);
	}
	resource.saveContents(contents);
	return resource;
	}
	resolve(uri: URI): Resource {
	const uriString = uri.toString();
	if (!this.resources.has(uriString)) {
	throw new Error(`In memory '${uriString}' resource does not exist.`);
	}
	return this.acquire(uriString);
	}
	protected acquire(uri: string): ReferenceMutableResource {
	const reference = this.resources.acquire(uri);
	return new ReferenceMutableResource(reference);
	}
	}